If you're starting from town, follow the directions to get to Lower Loop. Once past the peanut mine, look for two trails on the right. Left is wider and easier, and right is narrow singletrack. Both end in the same place. The trails wind through the woods on a very easy grade. It's great for one speed bikes and townies.
At the next intersection, look for a singletrack that climbs up the hill to the left. This is Upper Lower loop. The end of this trail dumps out at Gunsite Pass road. You have 3 options here. You can either turn back the way you came and go back down on upper lower loop, take a right and go down Gunsite Pass road to link up with the Lower Loop or continue up Gunsite Pass road and ride GB loop.