So, my alternate timeline, I decided to have it start during the War of 1812. But in order for my alternate timeline to work as planned, I need Russia to become allies with France under certain conditions.
So the War of 1812 is elongated so instead of lasting the 3 years it did in our timeline, it lasts 5 years.
The British are already at war with the French during this time. But part of Napoleon's army is sent to the South. The French are allies with the South. Here is the French empire at the time:
So, no reason why part of Napoleon's army can't be sent to the South since France has dominated Europe at this point. Except the Royal Navy which would likely obliterate Napoleon's army.
The British significantly hurt the North. In fact the North gets so much attention that the British don't really battle with France even though they are technically at war with France. Russia is also this way in the Napoleonic Wars for the most part. France is technically at war with Russia but Russia just acts as an observer state for the most part.
After 5 years, there have been times when the French were dominant in North America and times when the British were dominant in North America. The Americans were primarily against the British but they didn't mind France so much, especially in the South where they are allies with France. France and the UK sign a peace treaty.
This treaty allows the French army that allied with the Americans in the South to stay in the South and spread Parisian French throughout the South. It evolves into American French over the years and becomes co-official with American English. The treaty also promises that the British won't hurt the north as long as they get to integrate Seattle Bay into Canada. There is a special part of the treaty for Napoleon and his family. Instead of being exiled in the middle of the Atlantic Ocean, they will be sent to the South. The South, since it is allies with the French, welcomes Napoleon and his family and lets Napoleon become the first King of the South.
By this time, parts of the French Empire were lost and Napoleon has been defeated at Waterloo. But France has pretty much its modern border at this point:
But the North and the South are now separate countries. The capital of the South is Lafayette, Louisiana, the most French city in the South. The capital of the North moves from Washington D.C to Philadelphia, the historic capital of the USA so that the capital is not so close to the other country that it could easily be conquered.
Why Russia is Needed
So I figured Napoleon would probably send around 20,000 troops to account for the Royal Navy and death from natural causes at sea. Russia would, if it became allies with France, probably send around 100,000 troops for those reasons + protecting Napoleon and his army. Now the Russian Navy has never been all that big because the seas it needs for a navy either freeze up(the one by St. Petersburg and the other sea closer to Korea both freeze), or would be controlled by the Ottomans which wouldn't let Russians through(the Black Sea).
So the only feasible way to get those 100,000 Russian troops to protect the French Army would be to send them by land, to France. A feasible route would be something like this:
France would need to build all the ships for carrying both the Russian Army for protection and the French Army. But what I am wondering(besides the number of Russians who would need to stay behind for 5 years which I will ask about in a separate question) is how close or far the ships carrying the Russian Army would have to be to the ships carrying Napoleon and his army to protect the French Army enough for the majority of it to actually arrive at their destination in North America and would Russia ally with France if they knew the Royal Navy was a big threat to France if the French Army even tried to leave Europe?
Okay, someone asked how the Russian Army could protect the French Army from the Royal Navy. Well I was thinking about having all the ships move as a single unit and being close enough that all that the Royal Navy can see are Russian troops and thus Napoleon and his troops are safely hidden from the Royal Navy.