This cache is near the West Point of the Old Railroad Grade, where once upon a time, you could stop on your trip up Mt. Tamalpais on the "Crookedest Railroad in the World". Now, you can go by bike, or hike, or go on a zike-bike if you like (or a jogging stroller), but you cannot drive.
The cache is a painted tupperware container. The cache location is near the junction of many trails - Old Railroad Grade, Old Stage Road, Matt Davis, Rock Springs - and well marked on all Mt. Tam maps.