Just south of Ashford Mill Ruins where Badwater Rd meets Jubilee Pass Rd, you can continue down the unpaved portion of Badwater Rd/Harry Wade Rd to find a long sandy stretch that leads out of the park to the south. I'd recommend AWD with high clearance at a minimum as the road can be a little washboardy and sandy. There are ample dispersed camping sites along this portion of the road (use previously disturbed spaces within the 50 ft wilderness boundary). The sites are a little rocky/sandy but most looked fairly level and all offered remote, stunning views of the park with little traffic. We had one visible camper sharing the entire valley with us, couldn't ask for more.