Marin Municipal Water District: Rock Springs to Mt. Tam West Peak Loop

5.6 mile loop - Constantly varying grade up and down looping around upper parts of Mount Tam without venturing too low in elevation near the reservoirs.  Northernmost branch of hike on High Marsh and Kent Trails (north of Potrero Meadow) is strenuous down out and up back, and could easily be cut out by using Laurel Dell Road without venturing north of Potrero Meadow.