Start riding on Road W about 0.2 miles. Drop into the singletrack on the right. Pick up a "Big Loop" map at the bike shop. Lots of trails in the Dolores/Cortez area.
From Cortez, take Hwy 145 north 10 miles to Dolores. In Dolores turn left on 11th St (turns into CR 31). About 3 miles on 11th, and turn right on Road W. East on W about 1 miles, cross the cattle grate and park in the lot in the left.
http://www.singletracks.com/item.php?c=1&i=3547