From the South parking lot locate the low spot in the metal fence designed to keep out motor vehicles and lift your bike over the fence. This is the start of the trail. Ride west to Old Fairbank Road. This road is only open to authorized motor traffic and you should be able to make really good time because the road is well maintained. Follow the road South for 2.3 miles to the Boquillas Ranch. This is an official BLM facility. Ride past the buildings to the far Southwest corner of the ranch to find the trail leading South. There is a small sign marking the trail. About 3/4 of a mile South there is a junction near the abandoned railroad bed. If you ride the trail straight ahead it will end by the river at a very pretty spot with an interesting old abandoned car. To get to Boston Mill take the left fork at this junction and cross over the railroad bed. The trail gets very rocky and climbs over several hills. After about a mile.you'll come to a trail leading toward the river. The main trail continues South about four and a half miles to the Charleston trail head. This short trail leads to the remains of Boston Mill. Take a picture to prove you made it then ride back to the parking lot.