Robbers Cave has a few different campgrounds, but the 2 used for RVs without interest in the equestrian sites are Whispering Pines and Old Circle. We stayed in Old Circle, which offers more private, forest surrounded sites. Our site was 30amp and water for $22 a night plus an $8 reservation fee ($25 there are FHU sites), and there is a dump station on the way out.

Pros: large, fairly level, somewhat private natural sites, hook-ups worked fine; Robbers Cave has tons of trails (some are better marked than others) along with an interesting rock formation/cave/the namesake, that's worth a visit.

Cons: The road around Old Circle is single lane and leads to the dump site which is on a small hill, but the lay-out can make being trapped in the park and/or blocking the road out a problem. The dump site has a sign indicating it's $5 with no clarification as to whether campers also pay, and it was full and spilling when we went to leave. Our T-Mobile signal was nearly non-existent and only sort of useful with the booster. The side-by-side traffic (aka golf carts) can be moderately annoying (as a plus, they have a paid ATV park) and it was fairly common to see kids, sometimes with adults, riding the camp ground circle over and over.

This overall campground property is huge. We were there over Labor day weekend and it felt peaceful and not any more crowded than any other weekend at a state park.

Reservations: We stayed here over Labor Day weekend. When I looked online a few weeks before arrival, the reservation site said they were full. When I phoned them, they had plenty of sites available. They said it's better to book over the phone then online.

They take the first night's reservation + $8 reservation fee at the time of reservation. You can't pick your site over the phone, but you can put in a request. They assign sites the Sunday before arrival.

Sites:
You want to stay in Old Circle Campground. It's more private than Whispering Pines and the sites are larger. We liked our site (24) because it was a pull-thru and offered a larger "backyard" for the dogs. Site 32 also looked like an awesome spot. Sites are all paved and pretty level.

Activities
-Hiking: the best hike is at Robbers Cave itself. Lots of boulders to climb on and you get a great view at the top.
-Kayaking: We don't have kayaks (yet!), but this place really, really made me wish we did. There are several lakes and rivers to choose from in the area.
-Feed the mini-horses!
-They also have a pool, disc golf, mini golf, but we didn't partake

Connectivity
-My Verizon iPhone 6 had no service, but our Verizon mi-fi (791L-46B1) had 1 bar LTE and we were able to stream Netflix all weekend

Oh - and watch out for skunks, raccoons and TARANTULAS at your campsite!