You can get some very detailed maps of the Forest Service Roads at the Ranger Station in Mammoth Lakes. They are printed on newsprint, so they don't last long, but they are detailed and free. I don't know if they are topo, so you might not see steep elevation changes in the roads. That whole area is pumice, not always deep pumice but dusty. Do not drive to Mono Lake shore unless you are on the main road to see the Tufa at the State Park; the roads around the lake can be feets thick loose sand from the old Mono Lake shore - which takes a modified off road vehicle to maneuver.
