Yeah, I'm certainly not going for a 'Boston is the untouched remnant of pre-War society, ruled by a just democratic council, the people no longer fear the night and the streets are paved with gold, etc etc'
If the characters make any effort to reach Boston, it'll probably be more like 'You can finally see the sky scrapers (or what's left of them) in the fog. You can smell the salty sea air. You notice multiple gardens springing from old parks. People are tilling fields and getting ready to plant the next crop. Children play in a makeshift playground made of wood, like in the past. A group of guards, armed with hunting rifles and pistols, halt you a mile out and question you. After discussing your predicament, and showing that you mean no harm, they let you in. Congrats.'
Then the French attack 
Boston would most likely boast a bigger population, access to better trade (hopping along the coast) and the loot would certainly be better. It's no end-all-be-all, but they characters and their people might live a bit more comfortably.