SoNH here too (cripes, how many of us are from the same region here?!) - you're gonna be landlocked forever if you don't get yourself a car (or at the very least, a bike).
I'm not poly myself, so I don't have much in the way of Poly resources for you. My partner spends time between here and RI so he's meeting up with people in the MA area to find some sort of Poly community. There is a Boston Poly community that he and his OSO have found, so if you can get yourself to a train station, that may be viable.
I do like BG's suggestion of NHRD. My coworker skates with them (just went from the Seabrook Meltdowns to the Manchester Cherry Bombs, I think), and it seems like such a fun time.