Black2door- I used to go in the State Forest(Plymouth) The stretch between Long Pond Rd. and the Carver/Wareham entrance had some interesting spots.
Also if you go in the Plymouth Town Forest off Long Pond Rd, right after the high school there are some old fire roads in there that are not blocked. I seriously doubt if any of them are LEGAL to wheel on although I do not remember seeing NO TREASPASSING signs, you know you are not allowed to have fun in MA......lol....a former Plymouth resident.