Near Letts Lake, the South End Loop is a strenuous 24 mile trek ascending Goat Lake. A rigorous day ride for hardy bike riders, or a more moderate 2 or 3 day trip for those who chose to camp out along the way. Several good camping areas exist along the route. The developed sites mentioned above, with the exception of Old Mill and Dixie Glade, have potable water, vault toilets and garbage collection during the recreation season. It is important to note that the Deafy Glade Trail leaving Dixie Glade Picnic Area is open for horse and foot travel only. Mountain bikes are prohibited from using this trail which accesses the Snow Mountain Wilderness. The route uses a 2.7 mile portion of surfaced county road, with the rest of the loop being unsurfaced, low maintenance level Forest Service roadways, including a portion of the Mendocino Off-Highway Vehicle Corridor on Trough Springs Ridge. One of the highlights of this route is Letts Lake. This 30 acre lake offers fishing, swimming, non motorized boating and many other water based recreational opportunities. Other recreation opportunities are concentrated in the Fouts Springs Valley, where Mill Creek and the South Fork of Stony Creek merge. This valley offers access to one of the most popular riding areas in Northern California.
To reach the trailhead from I-5 on Maxwell/Sites Road to Sites. Continue west on Sites/Ladoga Road to Ladoga then continue west on Ladoga/Stonyford Road to Stonyford (28 miles). From Stonyford travel 9 miles west on the Fouts Springs Road (M10) to the Davis Flat/Fouts Springs Staging Area, or turnoff at 6 miles onto the Trough Springs Ridge Road (M5) and travel west about 7 miles to Old Mill Campground. To get to Dixie Glade, Mill Valley and Letts Lake continue west on M10 and follow the signs. Distances from Stonyford are respectively 13.5, 16, And 19 miles for these three campgrounds. All these areas can also be reached from 1-5 at Willows by traveling 22 miles west on State Highway 162 to Elk Creek and then 18 miles south on County Road 306 to Stonyford. This loop can be started from several staging areas including all Fouts Springs area campgrounds, Mill Valley, Letts Lake, Old Mill and Dixie Glade Campgrounds.
Overall, South End Loop Trail is the 30th most popular mountain bike trail of all 132 mountain biking in California.