How do I feel about Boston? I'm extremely happy with it, I've been hoping that rumor was true for a long time now.
I've visited Boston on several occasions, and if not for it being Yankee territory and having horrific winters I'd love to spend more time there. Historically it's a great choice for the franchise in my opinion, as part of what I really loved about Fallout 3 were the historical references. I've also visited DC on a number of occasions, and love it as well.
For me, Bethesda Fallout games simply require that Americana.
I've been saying for years that I would love to see a game set in New Orleans. I would have been extremely happy with this as well, maybe in eight more years.
As far as revisiting the West Coast, I think the originals handled it beautifully. It would feel cheap to try and revisit that now, IMO. I hope it never happens.
If I want to visit Redding, I'll fire up an isometic engine.