I was looking on the website that Winslow151 found and there are two campgrounds w/ heated bathroom open offseason but being from CT have no clue what they're like....
Shawme Crowell State Forest, Sandwich, 508-888-0351
October 10, 2005 through April 13, 2006
Thursday, Friday and Saturday night stays only, plus the Wednesday before Thanksgiving
Heated bathroom facility
No dumping station
No hookups
Reservations accepted
Walk-in available first come, first serve
Mohawk Trail State Forest, Charlemont, 413-339-5504
October 15, 2005 through May 4, 2006
Heated bathroom facility
No dumping station
No hookups
Cabins sleep 3 or 5 persons and are reservable year-round
Reservations accepted for cabins only
Tent sites are walk-in first come, first serve- call the park for road and accessibility conditions
Anyone from Mass know about these places?