For germany to face US it needs to win the land war and start a naval war, with luck while japan is still alive and kicking to make this a two front war.
US industry is powerful but it takes a lot of manpower and resources from other countrys. (I hated in HOI2 that US was self sufficient, it was far from reality in WWII as US needed to ration lots and lots of things).
If germany gets a navy strong enough to secure a route from france to canada it can start landing from there and start the war.! (Sorry canada XD).
Also the greatlakes have excellent chokepoints that can be used to secure a position and start the war from there!
If japan was still alive and kicking i would also try to send what i could to help them.
But i don´t see much hopes for japan as china alone could have won that war! (at great cost but they could).
US industry is powerful but it takes a lot of manpower and resources from other countrys. (I hated in HOI2 that US was self sufficient, it was far from reality in WWII as US needed to ration lots and lots of things).
If germany gets a navy strong enough to secure a route from france to canada it can start landing from there and start the war.! (Sorry canada XD).
Also the greatlakes have excellent chokepoints that can be used to secure a position and start the war from there!
If japan was still alive and kicking i would also try to send what i could to help them.
But i don´t see much hopes for japan as china alone could have won that war! (at great cost but they could).