I lived in the Roscommon/ Saint helen area for quite awhile. All the trails that way are accessible by ANY 4x4 vehicle (Jeeps, Chevy's, Ford's, Quads, Dirtbikes, etc, etc) as long as you have an ORV sticker, the Sticker is about 12 $ I believe at any of the gas stations in town, They just built a new Rock climbing area out by First crossing. (Your bound to end up over there, even if you start in the next town over). They have trails that go for MILES, I'm originally from the metro Detroit area so I know Michigan pretty well. They have a Saint helen, Roscommon ORV trail head around Dundee, MI somewhere I believe, towards the Ohio border, Which is 3+ hours away from Saint Helen.
If your headed past exit 222. Stop in Saint Helen. Your bound to find something there you like.