After learning that Bottomless Lakes State Parks do not allow campfires, and striking out at Lake Van (also no campfires and didn't look to be open in late September), we settled on the Carlsbad KOA to be closer to the Caverns the following morning - and they had campfire rings! 

The owners were very friendly and even showed us to our spot in their golf cart.

Your typical KOA with lots of camping amenities. Enjoyed a long hot shower and clean restrooms. We appeared to be the only folks outside their camper in the evening. 

Was a bit windy, but the landscape allowed for beautiful views all around and a gorgeous sunset.