For those of you fighting against the US:
The US starts out the game with
virtually no ground forces. It does have a considerable naval force in both tthe Atlantic and the Pacific, but not enough to be everywhere at once. A lot of the US navy is old DD's and relatively weak subs.
In the Atlantic, 3 BB's, 1 CV, about 6 CA's, 20 subs and about 130 DD's, most of them old 4 stackers. Air power in the Atantic is limited. Quite a few Peashooters with a bomardment rate of a whopping 4. Some B-18's with a bombardment rate of 8. And a couple of Dauntlesses and Vindicators with a more decent bombardment rate of 16.
There is an opportunity here for Germany and Japan. As soon as you have built a couple of DD Flotillas, try loading them up with a couple of SS Storm Troopers, or anything, for that matter, and send them over to the Western Hemisphere to raise hell. The DD flotillas are strong and fast. Try sending them North via Iceland and Greenland. Or get them into the wide open South Altalntic. The Panama Canal is very vulnerable in the early game. Only 1 conscript infantry and 6 subs stationed there.
The Continental US early in the game is virtually undefended by groind units and the units available to the US to produce are not very powerful. Those that have good offense have poor defense. Those with good defense have poor offense.
Remember, I am talking
diversion here, not a massive, full scale invasion.
The US fleet in the Pacific is more powerful, but the Pacific is much bigger and harder to cover. Alaska is undefended and acutely vulnerable to Japanese attack. Same for the Panama Canal. A Japanese human player could try and lure the US navy far away from the US and get it in a trap while landing some trrops in the Western Hemisphere.
Chile and Argentina can be your friends. Both countries like to build naval forces, to include BB's. If you can get them to declare war on the US, this will cause the US AI to divert forces to deal with them. If you can get an ROP agreement, you can land troops safely, hide them, and build them up for a surprise attack.
In the US scenario I am playing now, Peru declared war on me and there is now a parade of British ships heading East across the Pacific
AWAY 
from Japan to attack Peru and it's navy of 3 subs which I already sunk. The %#%# British Navy needs to be defending Australia.
Russia can also be useful before you attack it. If you can get Russia to go to war with England or the US (or take advantage of the opportunity when it does), you can get the US and Brit AI's to divert forces. Russian naval forces can be cause big distractions for the US and the UK. I recently had 30 USSR subs show up off Alaska and try to head down the US West Coast. Had to divert many naval units and air units to deal with them.
If you declare war on Brazil, watch the Italian navy head for Brazil and then watch the SU nave and rRoyal Navy chase the Italians while you infiltrate some DD flotillas loaded with troops into Canada.
Britain has a city in South America - Georgetown. If Germany can capture it early and use DD Flotillas to send reinforcemnts that will be a major diversion for the US.
Roads and rail lines connecting North and South America are vulnerable to shelling.
The road to Alaska is vulnerable to shelling and bombardment.
Havana, Cuba is an isolated target, with no/little defense early in the game. Possible place for air attacks on the US. You may not hold it forever, but again the idea is diversion.
The initial problem is to sneak past the Royal Navy in the Atlantic and get around the flank of the US Navy in the Pacific. The South Pacific is wide, wide open.
For Germany, this is easier once Germany has ports on the Atlantic (France, Spain, Norway) which increase the number of places you can build and launch ships and subs and dispatch DDF's loaded with troops without having to go through the English Channel and North Sea choke points. Use your existing capital ships to lure the British and US navies to one place while you send troop convoys in another.
In my limited experience and humble opinion, I think the
worst thing either Germany or Japan can do in the early game is to leave the US mainland alone and allow it to buld its economy and pump out forces undisturbed.
Some may think that some of this is unrealistic. And to some extent it is, given the limitiations of the game engine, etc. But if you want pure realism, then Germany and Japan lose - period.
The great thing about this scenario is that it is reasonably realistic, but even better, presents some real challenges for playing any of the major Civ's.
Sure, it may not be entirely realistic for the US to have invaded South America, but in a general sense the economic capacities of those countries were available to the West.
In the game, if the US does not invade South America then I am not entirely sure that the US could prevail over whoever wins in Eurasia - Germany or Russia. Japan may have a harder time there given the lack of good tank units.
Adler, unless you are trying to run convoys in the Med, then that is a good place for all those US DD's and CL's. What could they possibly do in the Med that could hurt you? They can't bombard, I don't think. If they are in the Med, they are not in the Altlantic. It is also a good opportunity to destroy them as you are doing, if you feel like it.
OVerlag, I agree with Adler about not attacking cities with stong flak. Good way to lose your air force. It is the old problem: do air units have to bomb to allow ground units to move in, or do ground units have to move in to take out the AA to allow air units to operate free of anti air attacks? This remains a real-world issue today.
OVerlag, I also respectfully disagree that Germany has no chance in the Atlantic against the US. Germany probably has to take down Poland, France, Spain, and Russia at least to the Urals before it can seriosuly challenge the US in the Atlantic. Germany needs to seriously expand its economic base to deal with the US. The Iowas can be a problem, but in 1.5 Germany has the Hindenburgs which should balance the equation. Also, you might consider saving up your U-boats. Wait until you have the exits to the North Sea and English Channel firmly under control and then send out large, mutually supporting wolf packs. I think U-boats in ones and twos just get massacred. Air bases in Iceland, Greenland, and the Azores are also useful. (Think DD Flotilllas). 50 or sixty U-boats hitting the North Atlantic simultaneously can be a hoot.
Rocoteh I hope you did not take my comments on DD Flotillas in my earlier post as too negative/critical. Was reallly just trying to pass on some observations and not trying to throw rocks. With or without DD flotillas, this is a truly great scenario and a great deal of fun to play.
As of right now in my US scenario,
all the German DDF's have disappeared from the Irish Sea, English Channel and North Sea and invasion attempts on England have stopped. No idea where all the DDF's went to or if they were sunk. I'll have to wait and see.
Unless you are new to Civ 3 I would strongly suggest playing this scenario at Deity or Sid level for the most fun.
Grizx