There is one active club I am aware of. This is all the info I have I found on the sledmass.org website. They have their own trails. I would have joined if I had not been "elected" secretary of the club I belong to in New Hampshire.
Nipmuck Trail Riders Snowmobile Club, Inc.
P.O. Box 33
Stafford Springs, CT 06706
Meetings 1st Tuesday of the month, Sept. through April 7:30 P.M.
Memorial Hall, Stafford, CT.