the great thing about BLM lands are that you can pull over ANYWHERE you are off of the road, and camp... yes, blm does have some campgrounds, but you dont need to look for one unless you want to... but you must strictly follow the minimal rules required to have a fire outside of a designated fire pit... a shovel and at least 2 gallons of water immediately available, as in a bucket or jugs setting not far from the fire. and during fire season, NO FIRES except inside a designated fire ring.
forest service lands are nearly the same, but some districts are becoming more limited, with more rules as to where and how you can and can not camp.... but there are LOTS of primitive, off the beaten path, out of the way forest service campgrounds that are free of charge and never full (except during hunting seasons)... some forest service districts do not allow an open fire to be built in the ground, but only in a portable fire pan..
I have found when one comes prepared and tries to be complaint, the rangers will give you a few reminders and wish you well....
but when one doesnt care and pretends ignorance, the ranger may cite you and/or at the very least tell you to leave...