Interesting place, a must for anyone interested in caves. We stayed on the tenting side of the campground and it was more of a primitive site (no water or electric). They do have sites with electric and water as well as an RV area. There is not alot of privacy in the tent area we camped at. They are very serious about not leaving food out because the wildlife is very active in the area. The bathrooms are very basic and the showers are in a separate building about 1/2 mile away. There is a fee of $2.00 to use the shower for 10 minutes. The camp store is very basic - like a small convenience store with a few camping essentials.
If you are going to tour Mammoth Cave I highly recommend that you reserve your tour in advance because almost all of them sell out (and there were 125 people on the tour I took!) There are more privately owned caves that are definitely worth seeing as the crowds are smaller and each cave and tour is very different.
Also I recomend that you do any grocery shopping before getting to this park as the nearest grocery store is about 27 miles away (Walmart).