Rattlesnake canyon- backcountry camping close to Carlsbad caverns- wayyy cooler than the KOA in town or the other camping options I've explored. Permit required but is free- pretty much anywhere far enough off the trail is fair game (obviously check with the ranger for the actual rules). We emerged from the caverns to see a sea of flames coming from the oil fields in what I guess is just south of the park. Gorgeous sunset- seemingly nobody else around though the rangers said there were at least a couple other parties out there. You'll want to bring a heavy duty tarp/ground cloth as many of the otherwise decent tent spots are pretty rocky.