North of Vail, the Lost Lake Loop is a 20+ mountain bike ride with awesome views. Starting from North Frontage Road in Vail, climb Red Sandstone Road north for a few miles. Veer right onto FS786 to the Lost Lake Trailheads. Follow the Lost Lake Trail (#1893) west for 3.5 miles back to Red Sandstone Road (FS700). Turn left and then right onto Red & White Mountain Road (FS734). After a couple miles, watch for the Buffehr Creek Trail (#787) heading south back to Vail. Or continue another couple miles to a doubletrack dropping off Buffer Peak (10,500) down to Davos Road west of Vail.
Overall, Lost Lake Loop is the 79th most popular mountain bike trail of all 176 mountain biking rides in Colorado.