This route meanders through a large, day use area in the Marin County Park System. There are no parking fees for this park, and the trails provide access to the Olompali trail network as well.
This route is a loop but if you decide to run from the San Andreas parking area to the Olompali State Park expect a 20-mile round trip run. Hours of operation and restrictions are different between the Marin County Open Space Areas and State Parks.
This longer loop mostly uses dirt fire roads for the trip. Starting from the parking area located on San Andreas Drive, the run will start with a mellow climb. Though the grades are mostly low, you'll consistently be climbing until the top of Mt. Burdell is reached.
Note that the top of the Mount Burdell Preserve features a handful of radio towers. These are on private property and are not open to the public. Instead, take in the sweeping views of the area and catch your breath. If you're not quite ready to head home, access the Olompali trails by passing through a gate which leads to the Upper Mount Burdell Trail
However, if you're ready to head back, continue on the Quarry Trail
to begin your descent. You'll be dropping elevation pretty quickly, and this portion of the park is much steeper. As you make your way along the final stretch of the Michako Trail
, you'll get a pleasant reprieve to finish out on.