Rated: Advanced. Single and double track, loop, variable terrain, cliff conditions so you need to dismount in one spot. Fast changing weather. Occasional joggers + horses. Lots of climbing with some good downhill. Can be clock-wise or counter clock-wise, but the CCW gives you the best downhill after lots of climbing.
Directions: In Boulder, use Flagstaff Rd. @ Chatauqua park go about 6 or 7 miles. Has A small dirt road on left (south) side to reach trailhead. Watch for cyclists climbing Flagstaff Rd.
From Golden, go north on Hwy 93 to Coal Creek Canyon dr. (Hwy 72) take a left and go approx 8mi to Gross Dam rd on the right, road may not be marked but it is ~.5mi past the Boulder County sign. Take a very sharp right onto this dirt rd (nearly 180deg) and go 2.7mi to the Crescent Meadow parking lot on the right, just past the railroad tracks. http://g.co/maps/7acb8