From the parking lot ride the trail East for 3/4 miles to the old railroad bed and turn right. Follow the bed South for .3 miles to reach the left turn to the Presideo. There is a toilet facility to mark this junction. There are plenty of signs along this trail. It is maintained to be easily walked. It is interesting to ride through the Presideo. The place was built in 1775 by the Spanish army but abandoned after an Indian massacre in 1780. There are only a few low adobe walls remaining but there are interesting signs to read. The trail will lead through the ruins and then meet back up with the railroad bed a short way to the South. Almost immediately you'll come across a trail on the left leading down to the river. This is the connection with the Fairbank Loop Trail it requires you to get your feet and tires wet (see the Fairbank Loop Trail). For this ride head South on the railroad bed for about two miles to the abandoned bridge. Crossing this bridge will connect with the Fairbank Loop Trail. For this ride turn around and ride back to the parking lot. You can bypass the Presideo ruins by keeping to the railroad bed if you wish.