Do not ride the horse trails, they are marked and no fun to bike on anyway.
Fort Custer Recreation Area has a fun and scenic collection of purpose built singletrack mountain bike trails. The trail surface is mostly hard packed, fast, and there is little elevation change in the whole area. There are unfortunately lots of short sections of soft sand, so stay on your toes.
This ride combines the two main loops, the Red Loop and the Green Loop, into one suggested ride. The Red Loop generally has a little more twisty but smooth riding. The Green loop is of the same general character, but tends to be a little more technical and has more straight and wide trail.
Need to Know
There is an entry fee to get into the park. It is currently $11 for an in-state yearly pass, $8.40 for an out-of-state day pass, and $30.50 for an out-of-state yearly pass. After the gate, follow the main road to the clearly marked mountain bike parking area.
There's hunting here in season, so be careful!
From the parking area, head to the obvious trailhead with a map posted. Head straight out and take the first right onto doubletrack, then the Red Loop starts on the right. Follow the signs to stay on the Red Loop until its end for this ride. There are scenic ponds throughout with abundant wildlife including birds and beaver.
All of the trails are well marked with signposts. These often give a name to the section of trail that is coming up. The trail winds sharply in a very fun manner through what seem to be old trenches for the first bit. It then turns into a typical mix of twisty smooth singletrack, short technical uphills or downhills, and straight stretches on wide trail.
You'll eventually end up just about back where you started and then you'll take the doubletrack path to the left. Soon the Green Loop will enter the woods on the left. Follow this trail around Eagle Lake until you once again end up back at the parking lot. There are both greater difficulties and longer sections of wide trail on the Green Loop.