I would try to find local groups of game developer types. I live in south-central Maine and there's a small group that meets about 30 minutes away, there's got to be something it eastern Mass. I wouldn't get your hopes too high about finding a suitable collaborator within easy driving distance, but there should at least be a number of people with similar interests.
Searching online is almost definitely a better option for finding skilled people to actually work with though, in my opinion. I worked with a small international group for six months to make a small game, it went pretty well. We communicated more or less daily on Slack, and had short weekly skype calls to make sure we kept things going.
I do live in the middle of nowhere though, so I may be biased, I'm sure there's a ton of people in the Boston area interested in this sort of thing.
