Actually, I didn't think of some of those. Mind if I add them to the story line?
Go ahead. But I'm a bit in doubt if Germany would be able to invade the US, even after a huge victory in Europe. The USSR wasn't able to do it (you could say they never tried, but still).
Germany would have to be very strong, with few casualities after the war. They would need to have good infrastructure and enough resources to build up a large army.
The US, on the other hand, would need to be passive during the whole war, so that when Germany invaded, they would be very surprised.
It would also help if Japan won the war in the pacific. If Japan captured China and Korea, they would certainly be strong allies for Germany.
