If you're in the Boston area, go check out Newtonville Camera. I know they're not in downtown but they've been around forever & are reputable. I remember shopping there when I was in high school, and have picked up stuff there occasionally when my travels bring me back to New England.
I'm more closer to W.B. Hunt in Melrose, but I'm not sure if they develop/print 120 in-house or send it out.