From the trail head, be ready to climb. It's just over a 7 mile climb to the turnaround point at the top. The climb is steep in sections with roots and some impressive rocks. There are also a few creek crossings. <br />
After turning around, the trail is a screaming downhill with some great natural flow.
Traveling on I-15, take the Boulder exit (164) and turn east towards Boulder. Turn left (north) onto the I-15 frontage road. Turn right (east) on Sloan Ln (your first right) and turn left (north) on Upper Valley Rd. Take your first right at the Muskrat Creek sign (Upper Valley Rd or Muskrat Rd). Keep left at all forks until you reach the trail head.
http://www.singletracks.com/item.php?c=1&i=8904