There are two trails: Torn Shirt and Murray Lake. Murray Lake is the easier of the two and is total of 9.2 miles in length. There are tight singletracks as well as fast sections. I would recommend for the beginner to intermediate riders. You can even cut the loop by 2 miles by forgoing the Lost Loop at the 2.7 mile marker. Torn Shirt is about 6 miles in length and is little bit more technical. Both loops start and return at the same parking area.
Exit Lee Rd off of US23. Go south on Whitmore Lake Rd on the west side of US 23. 1/2 mile south of Lee Rd. go west on Maltby Rd. After about 5 miles west (past two stop signs) turn on to Baur Rd near a bend. It's a dirt road from hence. Take the second left onto Silver Lake Rd which will take you to the Brighton State Park entrance.
http://www.singletracks.com/item.php?c=1&i=2340