Start at the Upper Miller Canyon lot. The trailhead will be behind the trail map in the parking lot (don't get it confused with the trailhead across from the lot that goes up - make sure you're descending). The trail will follow the left part of the creek until about halfway down when it crosses the creek.
It splits several times, but it's just re-routes from washouts. When the trail dead-ends into a gate at the bottom, hang a left and cross back over the creek. It will pop you back out onto the road. Make a left. From here, you can head back up to the parking lot or hang a right onto Perimeter Trail to Carr Rd to Clark Spring Trail #124 for a nice, challenging loop.