Most of these trails are dirt roads with sand, ruts, some mud, some hills and some washout type roads. Most are easily accessable by stock 4x4s.
The Mounds is east of Flint on Mt. Morris road. It has a little of everything, big mud holes, sand, ruts, small hills, scramble areas and trails etc. Because this area is pretty big, you would have no trouble in a stock Explorer if you avoid the big ruts and deep mud holes. I saw a guy in a small S-10 stock Blazer go through some incredible stuff in it and not get stuck.
GVSC had about 3,000 students when I started there, about 5,000 when I finished. I have to say it was some of the best years of my life. Played 4 years of football and met my wife of 22 years there. Lived in Kesler, Kissler, Kistler (SP?) dorm for a couple years. Man, those were great days!