Here I come to throw a wet blanket over things.
First of all, Washington (assuming that's him) and his army were not in upstate NY in 1777, they were in PA and NJ for the most part. Second, there were no large scale battles in dead of winter, as is depicted in this trailer. There were a few small to medium skirmishes (the most notable being Trenton, and that was against the Hessians, not the Redcoats), but for the most part both sides would set camp and stay there for the winter (see Valley Forge) and resume hostilities when the weather would permit.
This in no way dampens my enthusiasm for the game. But as I said before- if they're going to take on a piece of history as widely read as the American Revolution, they'd better be prepared to have their work picked apart.