I'd do something in Florida for two reasons, one because I am sick of deserts, I want tropical swamps and beaches and two, it's one of the most culturally diverse places in the US and I want to what happens when a melting pot goes nuclear.
Also, tribes of butt**** crazy hillbillies from the swamp riding mutant alligators into battle. You know you want to see that.
As for my favorite Fallout fluff... I really like Boomers for some reason. Lock a ton of NRA people in a bunker, let them simmer there for 200 years, step back and watch them unleash hell on the wasteland. It's hilarious but also very believable.