We went to Carlsbad Caverns several times over the course of a week. We took two trips into the main cavern, and a special tour to Spider Cave. Right now the main cavern is only accessible by the natural entrance as their elevators are currently broken. We enjoy hiking so we would’ve taken the natural entrance either way. The mile walk in is about a 750′ descent. All the rangers warned us – you have to come back up everything you go down.
Another massive stalagmite.
Once in the Big Room, it took us about 90 minutes to check everything out in the cavern. They do have a snack bar, but it consisted mostly of meat/cheese sandwiches. We brought our own food down, but you can only eat it in the dining area of the cave.