On the south shore of Boston. Are there any? I live in Bridgewater, a small college town about 30 miles away fromt the city. Are there any advocacy groups that enjoy riding in these areas?

Wow, no one has responded to this ad. What's even more pathetic is that I'm responding to it myself!

Welcome to BF.

Have you contacted these folks?
http://www.massbike.org/

I don't know about small towns around Boston but Boston itself is notoriously anti cycling.