You can camp in BLM or USFS lands. Depending on what type of camping you are planning on doing, like perhaps seeking a campground setting, you can call the Sky Forest Ranger Station in Twin Peaks near lake Arrowhead and they could most likely answer your specific camping interest questions since they cover the area of DCHS and the Bradford Ridge Trail Route. I don't have their number but you should be able to find it online. Contacting any San Bernardino Ranger Station should get you to someone who can get you the right number, and who to contact.