Need to get away from light pollution and cover yourself under a blanket of stars? Take a drive down to the Salton Sea area. It is a very large secluded area with many trenches to walk through and jump over. There are also train tracks across the street. A get out and stay out type of place.
Heading from the Los Angeles area, hop on the I-10 East, eventually keep righ to continue on CA-86 South signs for Brawley/El Centro/865 Expy, then a left on 195 East, then a right onto CA-111 South, shortly after you will be riding alongside the Salton Sea.
You may want to arrive while there is still daylight to scope out the place. You may park your car along the side of the road or in one of the many abandoned parking lots.
Once there, take your time, there are plenty of great opportunities to be had and areas to be explored.