Not without a PPP, please.
It depends upon how much detail you plan to put into the PPP. If you're going to plan in advance and document how each of our Military Units will get on their respective Galleys, you could play that far. If you don't want to go into that level of detail, then I'd suggest playing up until Turn 70, so that we will still have time to adjust the Unit logistics.
Units will need to board Galleys on Turn 72, so they must be one square away from a suitable Galley on Turn 71 (which could mean being one square away from Orleans for Units that will get on an Orleans-built Galley), meaning that Turn 71 is the critical turn to "get right" in terms of our Units' logistics.
It's also a bit hard to totally plan out the logistics as we're not totally certain what will happen when a Worker moves next to Germany's Cultural Borders--will Frederick ignore a Worker or will he hunt it down? If Frederick would ignore it, it might be better not to guard the Worker directly with an Axeman and perhaps just plan to have an Axeman at 1 E of Orleans in case of trouble.
But, on turns where we whip a Unit in Orleans, we probably also want to pile all of our nearby Units into Orleans, to make the City Defender pile appear to be relatively strong for any turn where a Unit (even a Galley) will exist in Orleans. So, it might just simply be best to pile both Axemen into Orleans on any turn where Orleans whips a Unit.
With so much whipping, that probably means nearly every turn.
Remember: Units on board of a Galley do not count as City Defenders, even if that Galley is inside of a City. So, we'd probably want to have our stack of Units inside of Orleans on Turn 72 and have our Units board our Galleys on Turn 72, then have our Galleys move into position 2 SE of London on Turn 72. That's a lot of logistics to "get right" in just 1 more turnset.
No, there's no room for a Chariot to go exploring. It's all hands on deck (literally, since we're putting the Units on the decks of Galleys

) if we want to stand a chance at capturing London! We'll be Chopping another Forest for Lyons to get the remaining Hammers that it will need for its Granary, so don't worry about Lyons not getting a Granary.
What good is further exploration going to do us if doing so risks costing us a loss in our first major battle?
Horse Archers are desperately needed, as they ignore Churchill's potential 2 First Strikes per Archer.
First Strikes can be incredibly deadly. If you haven't taken the time to look into combat odds, now is the time.
The second-best City Defender in London needs only 4 hits to kill our Chariot, and that's even with London's 60% Cultural Defences being dropped down to 0%. If that Archer gets in 2 First Strikes, that fact means that our Chariot will be
more than half dead before our Chariot even gets a chance to attack! To win, our Chariot would then need to win 8 rounds of combat before the Archer won 2 rounds of combat.
Now, the above image should not lead to the conclusion that Chariots will be useless in the attack. Far from it. Instead, we need to first damage the Archers before our Axemen and then Chariots will have better odds of winning the fights.
What's also interesting is that the Retreat ability (Can Withdraw from Combat) doesn't seem to work from boats! That fact is rather unfortunate, but I don't see a way to get around it, since, if we declare war and land our Units ashore, Churchill will almost certainly create another City Defender, which would mean even more losses on our side in the battle, and we also wouldn't know if our Spy was going to be successful at its Support City Revolt Mission before we attacked. In other words, the Flanking I Promotion will be
useless to our Horse Archer and thus our Paris-built Horse Archer is going to take the Combat I Promotion.
Which order we attack will matter for our Horse Archers, given how one Horse Archer can get the Combat I Promotion, and we'll want to use that Horse Archer at the right time, depending upon whether that Promotion can change the number of hits needed to beat the Archer or the number of hits needed for the Archer to beat us.
For example, it takes these many hits for various situations of having our Horse Archer fight against the Archers in London:
60% Cultural Defences, 1st defender, Combat I Promotion: 7 hits for us to win, 5 hits for the Archer to win
60% Cultural Defences, 1st defender, no Promotion: 7 hits for us to win, 4 hits for the Archer to win
60% Cultural Defences, 2nd defender, Combat I Promotion: 6 hits for us to win, 5 hits for the Archer to win
60% Cultural Defences, 2nd defender, no Promotion: 7 hits for us to win, 5 hits for the Archer to win
0% Cultural Defences, 1st defender, Combat I Promotion: 6 hits for us to win, 5 hits for the Archer to win
0% Cultural Defences, 1st defender, no Promotion: 6 hits for us to win, 5 hits for the Archer to win
0% Cultural Defences, 2nd defender, Combat I Promotion: 6 hits for us to win, 5 hits for the Archer to win
0% Cultural Defences, 2nd defender, no Promotion: 6 hits for us to win, 5 hits for the Archer to win
From the above numbers, we can see that if our Spy is successful, it will make our Unpromoted Horse Archers just as successful as our Combat I Horse Archer in the initial attack against each Archer, allowing us to save the Combat I Horse Archer to attack a wounded Archer for better odds.
But, if our Spy fails, and we decided to proceed with the attack anyway, our Combat I Horse Archer would have better odds than our Unpromoted Horse Archers, so we would lead with our Combat I Horse Archer if our Spy failed and if we still decided to attack.
Do we really need more espionage on Churchill? We have enough for our city revolt. I did spend one less turn with espionage since we already had enough.
Perhaps "enough" to perform the Mission, but likely not "enough" to put the odds of our Spy staying alive each turn in our favour.
At a bare minimum, we need to have spent more than the total EPs that Churchill has spent, if we want to give our Spy reasonable odds of surviving 4 turns of being stationary in London. Being over that number puts us on the right side of the 50% break point that is prevalent all over Civ 4. The odds of our Spy passively dying each turn that it spends in English territory go up if Churchill has spent more EPs (on any player) than we have spent (on any player), and vice versa.
We know that Churchill was putting a decent amount of his Commerce into EPs. He will have spent a decent amount of EPs on Stalin. Just how many is hard to tell--I've been trying to track EP Values in the thread, but no one else has done so, so the exact amount required is uncertain, and it's far better to make sure that we have spent more EPs than Churchill than to risk underspending and then having our Spy automatically passively die before even having a chance to execute the Espionage Mission.
More EPs earned (against any AI) makes Espionage Missions cheaper, even for Tech Theft Missions against Hatty by spending EPs on Churchill, so the EPs won't be wasted.
What could Churchill be building in London right now? Churchill has 51 Hammers in a build item. He has already build a Barracks and a Granary, so that leaves a Lighthouse (54 Hammers), a Library (79 Hammers), a Worker (52 Hammers), or a Settler (97 Hammers). A Lighthouse or a Library is unlikely given that London is at Size 3.
If we have more info on London's City Sizes (has it been growing and whipping? has it stayed at Size 3 this whole past turnset?), it would be easier to predict what he's building. It would also help if we had London's Espionage screen (Ctrl + e) values from a couple of turns, say, Turn 62 and Turn 64, for Sabotage Production and Support City Revolt, to see if he's been building the same build item all along or if he's been building multiple build items.
On Turn 60, Churchill hadn't started on his next build item and London was at Size 3.
On Turn 48, 2080 BC, we saw from the Top 5 Cities that London was at Size 5.
On Turn 38, 2480 BC, we saw from the Top 5 Cities that London was at Size 4.
What we do know is that Churchill makes a decent amount of Food + Hammers per turn with some form of Food source (or maybe two of them), a G Stone Quarry, and a settled Great Prophet.
Assuming two 6-Food squares, that would be:
City Centre = 2 F + 1 H
6-Food square = 6 F
6-Food square = 6 F
G Stone Quarry = 2 F + 3 H
Great Prophet = 2 H
3 citizens = -6 F
Total = 16 Hammers per turn, giving him 51 + 16 + 16 + 16 = 99 Hammers after 3 turns, aka 1 Settler (if he's building a Settler instead of a Worker) plus 99 - 97 = 2 Hammers of overflow.
Of course, if there's a 5-Food square in there, he would make 15 Hammers per turn, giving him 51 + 15 + 15 + 15 + 15 = 111 Hammers after 4 turns, aka 1 Settler (if he's building a Settler) plus 111 - 97 = 14 Hammers of overflow.
He might also 1-pop-whip a Settler, giving him significant overflow Hammers, too.
I would suggest that when we get to Turn 73, we don't perform the Espionage Mission until we've had a chance to do some more testing. If, for example, there are 3 or 4 Archer City Defenders, we'd want to play out some test games to see what our odds of success would be, and if our odds would be poor, especially if Churchill has a Settler in London at the time, we'd probably need to wait on our attack until he sent out his Settler Party.
With any luck, Churchill will build something else after the Settler (a Lighthouse?). Realistically, he'll build Settler -> Archer -> Archer, and then we hope that with 4 Archers, he'll send out a Settler Party, allowing us to attack when there are only 2 Archers defending London. With any luck, we'll be able to strike before the likely Archer that comes after a Settler gets built.
If we start documenting the following values every turn, we might be able to consider landing troops on Turn 73 and attacking from land on Turn 74, depending upon the situation and therefore based on what Churchill may already be building. We'd want to track:
i. London's Sabotage Production value (Ctrl + e screen)
ii. London's Support City Revolt value (Ctrl + e screen)
iii. London's City Size
iv. Whatever build items London has completed when its Sabotage Production value is missing
Note that if we landed before attacking, we would NOT perform the Support City Revolt Mission on Turn 73, as that Mission only lasts for the current turn. So, such a possibility is also another reason not to perform the Support City Revolt Mission on Turn 73 until we've had a chance to assess the situation.