There are two loops and I hear a third will be constructed. The Torn Shirt loop is just over 5 miles long. It's a nice dirt ribbon of singletrack that is fairly technical at times. Most riders will consider this an advanced ride. This shouldn't be taken that it's unrideable for less seasoned bikers. Give it shot.
The Murray Lake Trail is a more moderate ride. Traveling between 7 and 9 miles long (depending on which loops you take), it's a longer ride that will still challenge better riders at times. A great day of riding would include doing each trail twice.
Both trails are marked and easy to follow.
How to get there:
West on I-96 to Exit 147, through Brighton app. 6 miles to Chilson Road, south on Chilson to Park HQ, then east on Bishop Lake Road to the Trail Head.
Brighton is a close drive from Detroit, Lansing, Ann Arbor and Flint.