A late response is better then no response. I'm in southeastern MA myself. Wish there was more activity down this way. I love social nudism. Closest in this area would be Sandy Terraces in Marston Mills. Unfortunately not all that single male friendily last time I inquired.
Birch acres is now Berkshire Vista, I haven't been there in many years but I'm told it is still nice, incredible views and location. My band played there in the early 80's, great group of people! Lots of aging hippies. The Uk seems to have a large naturist community!