If you start out of the parking lot by the beach at Grousehaven Lake & pretty much follow the numbered posts, you can do about a 12-14 mile loop. There is a small section early on where you are on the road for maybe a half mile. You will also need to carry your bike across the swinging bridge near the back of the park to continue on the trail. Between markers 5-8 I believe, is the most challenging part of the trail. About a 3/4 mile climb, followed by a great descent of the same length. There's a few other hills near the beginning, & after that it's just a nice scenic ride.
2013 mtb trails - Midland City Forest, Gladwin County Rec Area, Jailhouse Trail, Ogemaw Hills Pathway, Glacial Hills, Rifle River Rec Area, Hanson Hills, Hungerford Lake, Burchfield, Bennett Park, VASA Singletrack, Mid Michigan CC, Potawatomi, Big M, ILRA