Unfortunately, we were visiting Carlsbad Caverns during Memorial Weekend, which meant dealing with big crowds of people everywhere. But as we knew that it was unavoidable, we decided not to let it spoil our time there. We started our visit to the park by going on two self-guided tours on the Natural Entrance and the Big Room routes. It took us around 4h to complete both of these tours even though their total length is only 2.25 miles (3.5 km)... That should give you a good idea on how much time we spent admiring various rock formations and taking pictures of them. It also made me realize how super-patient my husband is, who did not utter a word of complaint during that whole time.
I would strongly recommend renting an audio guide for the tour - we found it very helpful and it also made our experience much better.
The Natural Entrance route is 1¼-mile long and follows the traditional explorer’s route, entering the cavern through the large historic natural entrance. It descends quickly more than 750 feet into the earth:
Here are some of the interesting rock formations that we saw on the way down:
The Natural Entrance route ends where the Big Room route starts. The Big Room route is a one-mile walk around the perimeter of the largest room in the cave (of the size of 6 football fields!), passing through many highly decorated formations. One more beautiful than the other:
The Big Room can also be reached by the elevator, which is also used to get back to the earth's surface at the end of the trip.
Other posts about Carlsbad Caverns.
Practical info: Carlsbad Caverns does not have a campground or lodge, but there are plenty of them in the nearby city located just 2 miles from the entrance to the park.