This is an easy to moderate trail across the Chariot Mountain. It is around 11 miles long and runs between the S-2 and highway 78. Access is from highway 78 at the Banner store or from S-2 as you reach the flat after passing through Box Canyon. Description below runs from the S-2 to highway 78.
As you hit the valley after dropping through Box Canyon you will see the start of the trail on the right. It is marked with a small marker. Turn right onto the dirt road and proceed until you see another sign pointing up a wash to the right. You will go through the wash and then start to climb and the road will become rocky. At about 3 miles you will see a fence and a road to the left. This goes down to the stream and what appears to be the ruin of an old house.
Trail continues straight ahead and up the mountain. Trail is steep in parts and climbs through a series of hairpin bends. Very narrow and with drop-offs in places.
Once you reach the top it is an easy drive. After crossing the cattle grid, you exit the State Park and are on public land. There are several mines here so stay on the road unless you want a run in with the miners.
At about mile 11 the road splits three ways. Stay on the center track. This will take you down to highway 78. There is a gate halfway down the hill that looks as if it is locked but it isn't.
It looks like Google maps is now calling this trail Mason Valley Truck Trail.