We camped two nights last week in Loop A, the tent only, nonelectric section. Being mid-week, there were not many people, meaning it was also nice and quiet. The sites are roomy, with a large tent pad, fire ring, picnic table, lantern hook, and a food storage locker. Yes, this is bear country, but we didn't see any during our visit. The bath houses are as nice as you're likely to find in a national park, with flush toilets, hot showers, and an outside sink for dish washing, etc. There is also a large, wheelchair accessible bathroom with roll-in shower. A water hydrant is available to fill jugs and tanks.
We drove through the other loops to see what they look like, because Loop A isn't open in winter. Should we decide to camp here in winter, Loop B is the only section open. But, that will let us use an electric heater.
Be aware that some things are not open in 2020 due to Covid-19. The park visitors centers are still closed, the swimming pool wasn't open mid-week, and the check-in building was unstaffed when we arrived. There was a sign at the check-in point telling us to reserve and pay for our site using Recreation.gov. We had cell service there, so no problem. It you don't have service, drive across the road to the Camp Store (which is not always open) to use WiFi there. There is a note on the front door with the password.
There are so many things to do in Big South Fork and surrounding areas that you really need to just visit the park website and make a list of things to do. Some are easy and roadside, others not so much. For example, to hike the Twin Arches Loop Trail, you'll drive several miles of dirt roads to reach the trailhead and end up hiking about 6 - 6.5 miles. The description says the loop is 4.6 miles, which is true, but you have to add another 1.4 miles for the out-and-back from the parking lot to the start of the loop. The loop trail isn't bad, but the access trail has steep stairs. Anyway, find something you like and enjoy the Cumberland Plateau.