Reading reviews on Tripadvisor Mammoth Cave forum, I contemplated hard whether we should stay at surrounding campground (such as Nolin Lake) but I am glad I settled for this one. We went on 8:45 am and 7:15 pm cave tours and if we were camping in Nolin Lake, as it turned out, it would have taken a good half-an-hour drive including (albeit) a free fun ferry ride over Green River to get to the park visitor center where the tours began. I've read that early morning tours are the least crowded, but on my tour there were still good number of people, maybe around some 40 or 50, so I don't know how many people are on that tour later in the day. As I remember, the full tour capacity is something like 100 or 200. Lantern tour in the evening was fun, too. We also went to a couple of surface tour too, and it was nice to just get up and go at the time of those tours.
The campground is only 5 min ride on bike from the visitor center - a very pleasant ride. You can also hike there through a short trail in the woods past amphitheater where rangers do evening campfire talks. We didn't get to go there, but we wish we had.
Our old bikes came in handy to go to camp store, where shower, laundry and post office (surprised, but a nice touch) are also located. Bring headlights too in the evening, as it gets a little dark after the sun goes down. Shower is $2 per generous 10 minutes. I heard people complaining it is too expensive, and it may have been so, but you can return the tokens you didn't use to the store and this shower at Mammoth Cave was hot and had good water pressure, and lasted long enough for me to come out refreshed. Mind you it's not a hotel room shower, but it's clean enough and definitely serves the purpose. I thought the laundry in an adjacent room was also a very nice touch - it cost me $1 both for washer and dryer to use. Old machines, but they were such wonderful things to have around when our clothes got drenched wet & muddy after hiking in thunderstorm!
I liked fire rings at campsites too - I've never seen a fire ring on a campground with a grill that can adjust its height. I thought that was pretty cool.
Also, the picnic table - at first I didn't like the fact that it was not a wooden table that I'm used to, but I quickly realized that this 'cement' table was slightly bigger, and also, I can potentially, actually *cook* something there, IF you bring a Lodge charcoal tabletop grill or something (which I didn't, but I wish I did). But one must always use fire ring in the campground, to make fire, so be aware of that. Lodge tabletop grill is sort of encased, so I thought it would work on this table, though. Anyway, I thought this was an interesting difference from our camping experience in New York and Maine.
WiFi is available just outside of the campground office as you enter the premise. There is a picnic table there and you'll see people sitting there hovering over their cell phones and laptops.
The ground is flat, so that's good news for tent campers. There was a paved area for cars, and I liked to keep dish buckets on there, keeping it from mud splash from rain.
Bathroom is air-conditioned and very clean! This was the first time for me to camp in a southern state and this made sense to me as it was muggy and hot outside. I was used to cobwebs at campground bathrooms, but no such things. A nice touch!
About the crowd on the campground - it was an interesting situation, because while we stayed on the campground for four nights, we experienced a thunder storm on the second night. People seem to have dissipated - but the next night was Friday I believe, and the place was almost full, and also a bit noisy because some people kept talking into the night - they weren't particularly loud or anything, but they just won't stop talking until past midnight, and as a tent camper, that was not a good situation.
As some reviewers point out, some sites may be a tad too close to the road - so I would pick sites carefully.
As for bugs - there were some of those yellow jackets but they didn't bother us. What was great though is that I had no mosquito bites from 4 days of camping, thanks to the wonderful bats of Mammoth Cave!
Overall, we had a great time camping there. People were friendly and the caves, biodiversity, and histories of the place were just so interesting - it is deservedly a World Heritage Site.