From the Parking Lot, take Yucca or 10Bridges to Center Road. You can't miss it. It is the only 'road' in the trail network. It is a fairly smooth section of doubletrack. To the left you'll find Outer Loop and Airport Loop. To the left you'll find intersections with Porta Potty, Outer Loop (the west end) and Elevator/ XMAS TREE. The rockiest section is between Outer Loop and 10Bridges. Sometimes parts of the trail can be muddy and a few parts have standing water pretty much year-round.