doubt much info from the snowmobile clubs, most trails are on private lands and impassable due to mud.... ask me how i know that one. your best bet is check the chamber of commerce and talk to maine guides. id bet thats your best bet. i know some that have jeeps and buggies. ask around.
Look in to the Western Maine Mountain Jeepers club. It is based out of Bethel, not too far from you.
They have access to plenty of trails on private property for club trail rides. I have a place in Stoneham and joined this year. Many members travel a bit for the rides, and it is worth it. http://www.jeepmaine.com/
Mine:2003 TJ Rubicon Flame red, 5 speed, 4.88 gears, rear Detriot locker, RE 3.5" SF, 1" BL, 1" ML, MT/Rs 35" x 12.5 on Soft 8s, PSC Rocker Knockers, Warn 8274, Warn 620 flood lights, GP Fab rear bumper / tire carrier, MCE 4.5" fenders
Hers:2009 Wrangler X six speed soft top, one option = AC, Rubicon Tires and wheels
Mid-Maine has Maine4x4.org. Northern Maine has a club too, PMWD? or something like that.
Good places to wheel are all over, but BE CAREFUL. You will loose your rig if you get caught wheeling on posted land. No kidding. Stay out of the power lines, CMP will prosecute and will take your ride.
All Wheels Off Road Park in Lewiston is good, as is RMTP. I think RMTP is closed in the Winter. Join a club and wheel with friends. Best bet in Maine. Tote roads around Rangley, Moosehead and Brewer are good bets too.
It's a haul to get there, but the northern end of Moosehead and further north into the North Maine Woods is great. Hundreds of miles of dirt road, campsites, lakes and ponds, old trails nobody has been down for decades, just waiting for you to go check it out. The NMW charges a daily fee though, so a bit of research is helpful. http://www.northmainewoods.org/