It blew me away you could walk so many miles underground. This is an impressive stop and took my family by surprise how amazing it was. We were on an RV trip in July, and this was our first stop. There were large vehicle spots for those traveling in an RV or those towing something. I would suggest getting there in the morning by 10. We had no crowds, but when we finished our touring, there were heavy lines extending in to the gift shop. There is a ton of walking, and if you choose to walk down, you can take the elevator up, or vice versa. There are benches and various spots you can sit and rest along the path. There were many people taking breaks. We definitely did not want to walk back up. if you have someone who would have trouble walking up or down a long graded path, they can still take the elevator down and tour the bottom of the cave. I highly recommend!
Site was clean...even after 4th of July weekend. Made reservations online about a week in advance. The site made a general statement to check with any of the parks if you are arriving late as there may be gates that are locked. The hours said the park closed at 10pm and we arrived just before that. There was noone at the entrance, but we were able to go on in as there was no gate. Our name was on our reserved campground, so all was well. Generators have to be shut off from 10pm to 7am for quiet time, but it was cool enough even in July, so it was quite comfortable in the RV. There are no RV hookups for this campground as an fyi. The next day we packed up and drove to the Goblins and wore ourselves out climbing. Probably my favorite part of our trip.