Don't panic at the size of the REF -- they don't come at you all at once, but in waves of 4, 8, 12, or 16 units (at least, 16 is the most I've seen in a single turn). So all you have to do is to beat the first few waves without losing too many (or ANY -- see below) units, and then get the survivors healed up, whereupon all the promotions you've gotten will make the follow up waves much easier to handle.
Preparation should start long before you declare independence. First, you want to get as many Founding Fathers (FFs) as possible, which means building up bells like crazy. Yes, that will cause an early buildup of the REF, but for once, size isn't important.
Build several privateers as soon as you can afford them, and build up combat points (and thus combat FF) by taking out your rivals' shipping.
Build up a huge cash hoard by exploring early and often, tripping the "goodie huts" and getting the first contact cash for each native city. Then, start trading guns and horses with the native tribes, since those goods give you the biggest profits, regardless of what the little icon to the right of the city SAYS they want. If you're having trouble keeping the natives happy (shouldn't be a problem on easier levels), only trade with the native cities on other continents, since they can't come after you.
Then, spend that cash hoard buying enough guns and horses to make EVERY one of your citizens into a dragoon when the time comes. Store the guns and horses that won't fit into your warehouses on those cheap wagons for the time being.
Converted natives won't fight for you, so as you near the date for declaring independence, turn them all into colonists, either in the university in your main city (which should be kept full with three students at all times), or in the native villages learning to be expert fishermen or farmers (which you will need in the early- to mid-game to pump up your population levels.)
Drop missions in lots of nearby native villages -- a good source of those converts you'll need to get your population up.
Build only a few cities, all closely packed together. Use your hardy pioneers to build roads in EVERY square inside your civ boundaries, plus one square outside the edges of your boundaries.
Shortly before declaring independence, cut down ALL the trees on
1) the ocean-bordering squares right next to your coastal cities
2) the ocean-bordering squares right next to coastal native villages inside your civ boundaries
3) the ocean-bordering squares one square outside your civ boundaries
since those are the places where the vast majority, if not all, of the enemy troops will land, and you DON'T want to give them that crucial defensive edge provided by trees.
Shortly before declaring independence, turn all your citizens except for one placeholder in each city (preferably a recently coined native convert) into dragoons, and then go take out rival civs and natives one at a time (don't take on everyone at once, unless you're way confident of your military skills), until you've gotten all of your units the first couple of promotions.
Promote one dragoon in each city into a medic, and then put them to sleep there and never take them out. They will allow your dragoons to heal up fast enough so you've constantly got a fresh supply of fully healed dragoons to contend with the REF waves.
Promote quite a few dragoons into skirmisher specialists. These units will be used on the toughest troops in each enemy stack, knocking back their health and then allowing most of your skirmishers to retreat from combat, to heal up and fight another day.
Promote most of the remaining dragoons with the combat bonuses that give them increments of 10% increases in strength.
Kill the REF troops as soon as they land, using your dragoons, which should have a six square range of movement (with the movement bonus given by one of the FFs, plus the doubling from the roads that should be in EVERY square within your civ boundaries).
Before you go to war, park each of your privateers inside a native coastal city, equipped with a horse and a gun aboard the privateer to trade.
Save the game before each dragoon attack, trying out your strongest troops on the enemy soldiers with the worst combat odds for you among the various defending stacks of soldiers (you should have an exact percentage of probability pop up, such as saying you have a 33.2% chance of winning.) If you win the battle, save the game -- save the progress. If you lose the battle, reload the game (thus not losing that troop) and try again with your strongest troop on the weakest available enemy stack. If you still lose, reload the game again, and then send your best skirmisher against the weakest enemy stack, hopefully knocking back that defender's health while allowing your skirmisher to retreat. If you still lose, you're facing a really bad roll of the triggering mechanism, so reload the game once again and make a trade with a native city using one of the privateers noted above. That will trigger a (hopefully) better combat environment, allowing you to try your strongest available dragoon on the weakest available enemy. You should almost certainly win this time, and then save the result. If not, reload, and try with a different trade in a different native city, getting yet another combat trigger to try.
If all this fails, bite the bullet and send your weakest, most unhealed dragoon against their strongest troop as a sacrificial lamb. (Surprisingly, the one time I had to resort to this, this lowly troop managed to retreat, when the strongest dragoon skirmisher would have gotten killed. Go figure!)
Once you've taken out the top enemy or two in each stack, you'll likely be facing really good odds, 80% to 99.9% chances of success. Use your weakest dragoons against these cannon fodder, allowing them to build up promotions.
Using this "save the wins, reload the losses" exploit, it is possible to take out the entire REF without losing ANY dragoons at all.
If you feel you must rationalize this technique, think of this as you having some incredibly proficient spies and generals.
If you're thinking, wow, this is cheating, I'm gonna take whatever happens with no resaving, feel free to lose dragoons right and left. Make sure you personally are the one to contact their grieving widows, though, since it's your damn fault they died for no reason.
Happy hunting!
Preparation should start long before you declare independence. First, you want to get as many Founding Fathers (FFs) as possible, which means building up bells like crazy. Yes, that will cause an early buildup of the REF, but for once, size isn't important.

Build several privateers as soon as you can afford them, and build up combat points (and thus combat FF) by taking out your rivals' shipping.
Build up a huge cash hoard by exploring early and often, tripping the "goodie huts" and getting the first contact cash for each native city. Then, start trading guns and horses with the native tribes, since those goods give you the biggest profits, regardless of what the little icon to the right of the city SAYS they want. If you're having trouble keeping the natives happy (shouldn't be a problem on easier levels), only trade with the native cities on other continents, since they can't come after you.
Then, spend that cash hoard buying enough guns and horses to make EVERY one of your citizens into a dragoon when the time comes. Store the guns and horses that won't fit into your warehouses on those cheap wagons for the time being.
Converted natives won't fight for you, so as you near the date for declaring independence, turn them all into colonists, either in the university in your main city (which should be kept full with three students at all times), or in the native villages learning to be expert fishermen or farmers (which you will need in the early- to mid-game to pump up your population levels.)
Drop missions in lots of nearby native villages -- a good source of those converts you'll need to get your population up.
Build only a few cities, all closely packed together. Use your hardy pioneers to build roads in EVERY square inside your civ boundaries, plus one square outside the edges of your boundaries.
Shortly before declaring independence, cut down ALL the trees on
1) the ocean-bordering squares right next to your coastal cities
2) the ocean-bordering squares right next to coastal native villages inside your civ boundaries
3) the ocean-bordering squares one square outside your civ boundaries
since those are the places where the vast majority, if not all, of the enemy troops will land, and you DON'T want to give them that crucial defensive edge provided by trees.
Shortly before declaring independence, turn all your citizens except for one placeholder in each city (preferably a recently coined native convert) into dragoons, and then go take out rival civs and natives one at a time (don't take on everyone at once, unless you're way confident of your military skills), until you've gotten all of your units the first couple of promotions.
Promote one dragoon in each city into a medic, and then put them to sleep there and never take them out. They will allow your dragoons to heal up fast enough so you've constantly got a fresh supply of fully healed dragoons to contend with the REF waves.
Promote quite a few dragoons into skirmisher specialists. These units will be used on the toughest troops in each enemy stack, knocking back their health and then allowing most of your skirmishers to retreat from combat, to heal up and fight another day.
Promote most of the remaining dragoons with the combat bonuses that give them increments of 10% increases in strength.
Kill the REF troops as soon as they land, using your dragoons, which should have a six square range of movement (with the movement bonus given by one of the FFs, plus the doubling from the roads that should be in EVERY square within your civ boundaries).
Before you go to war, park each of your privateers inside a native coastal city, equipped with a horse and a gun aboard the privateer to trade.
Save the game before each dragoon attack, trying out your strongest troops on the enemy soldiers with the worst combat odds for you among the various defending stacks of soldiers (you should have an exact percentage of probability pop up, such as saying you have a 33.2% chance of winning.) If you win the battle, save the game -- save the progress. If you lose the battle, reload the game (thus not losing that troop) and try again with your strongest troop on the weakest available enemy stack. If you still lose, reload the game again, and then send your best skirmisher against the weakest enemy stack, hopefully knocking back that defender's health while allowing your skirmisher to retreat. If you still lose, you're facing a really bad roll of the triggering mechanism, so reload the game once again and make a trade with a native city using one of the privateers noted above. That will trigger a (hopefully) better combat environment, allowing you to try your strongest available dragoon on the weakest available enemy. You should almost certainly win this time, and then save the result. If not, reload, and try with a different trade in a different native city, getting yet another combat trigger to try.
If all this fails, bite the bullet and send your weakest, most unhealed dragoon against their strongest troop as a sacrificial lamb. (Surprisingly, the one time I had to resort to this, this lowly troop managed to retreat, when the strongest dragoon skirmisher would have gotten killed. Go figure!)
Once you've taken out the top enemy or two in each stack, you'll likely be facing really good odds, 80% to 99.9% chances of success. Use your weakest dragoons against these cannon fodder, allowing them to build up promotions.
Using this "save the wins, reload the losses" exploit, it is possible to take out the entire REF without losing ANY dragoons at all.
If you feel you must rationalize this technique, think of this as you having some incredibly proficient spies and generals.
If you're thinking, wow, this is cheating, I'm gonna take whatever happens with no resaving, feel free to lose dragoons right and left. Make sure you personally are the one to contact their grieving widows, though, since it's your damn fault they died for no reason.

Happy hunting!
), but my fleet of three frigates was no match for the eight or nine MOW the French king sent over. My warehouse in Quebec was overflowing with weapons (turning out about 50 per turn), and was my largest city at about 24 in its population with about 65% revolution support. Unfortunately, I couldn't get enough tools to complete a ship-of-the-line and a fourth frigate I had waiting to be launched at the shipyard, but they wouldn't have done much good against stacked man-o-wars anyway. Three smaller towns were producing about 30 food per turn, in addition to sustaining their own small populations with food. As new colonists were born, I sent them to Quebec to pick up weapons and return to garrison their hometowns. 