Nice an alternate setup for the same board. Good idea!
Really only need to change setups and development of a new political situation. Then use the same mechanics of whatever version of map you play 42, 40, or other global varrients. The hard part is establishing a balance. But you are creating it from scratch, so any bonus income, setup etc. Is adjustable to create the best balance.
Wildcat’s point on resistance makes sence. Possibly allow revolt if no units are in occupied zone. There are different partisan rules on here or make your own. If you want to resurrect the occupied and dead nations.
I dont have amerika, but I believe it is later in timeline so you could borrow some tech etc. From the varrient.