We found this great dispersed site (free US Forest) just off the Tunnel Road sign for the Mt. Figueroa campgrounds. There is a dirt road that takes you there but it looks like you might need AWD/4WD during rainy seasons since the road had some deep ruts. We came when it was dry season in a 2WD Eurovan w/ regular street tires.
We camped at the end of October (high temp was upper 80s, low temp was lower 60s) and there were still many flies so be sure to bring netting or repellant. The slightly unlevel site offered a great sunrise view as well as a sunset view over Sawmill basin.
We didn’t see any other campers around us. Even though we camped by the side of the dirt road, no one passed us the whole night.
Coordinates: 34° 44’ 0.480 N 119° 59’ 26.850 W