A lot closer than the Dakotas
The other day drove along a road that I have never been on before. Past some of the most interesting "badland" formations I have ever seen. Unusual sandstone formations and multi-hued mineral deposits.
This is in the Mecca Hills or the Orocopia Mountains which is about 2 hours north and east of San Diego. Just north of the Salton Sea.
Easiest approach is to leave Interstate 10 east-bound at Indio and drive southeast on County Road 111 towards Mecca.
Turn left (north) at 66th Avenue East and proceed north up to Box Canyon Road. Eventually this road connects with I-10 again.
The surrounding topography is managed by the BLM and has a variety of off-road trails. But the views one can enjoy from the road are well worth this detour.