If you are going to Nashville, you might like a detour to Memphis. On, Mud Island, there is topographical sculpture of the lower Mississippi River. It has historical information along the walkway. It is a beautiful piece of artwork. I believe it is free and the parking is good. Across the river in West Memphis AR is a very nice campground, Tom Sawyers.
One Forum user asked about putting seating on their PC roof to watch Indycar races. Save your roof. Barber Motorsports in Birmingham AL is a wonderful place to watch the races. It is built for spectators. You can see the track from a picnic blanket, lawn chairs or through your windshield. There are no bad seats. If you like vintage motorcycles, there is a museum at the park.
One of our favorite places is the Fairport State Campground in Muscatine IA. They have porch swings at the water's edge. It is beautiful in the Fall. We pretty much like being anywhere on the Mississippi River, especially the Locks and Dams.
The Spearfish City Campground in Spearfish SD is a wonderful place for families. They have a restored historic fish hatchery on site.. Bring your bikes. The bikepaths follow the river for several miles. Playgrounds are nearby and it's an easy ride or walk to downtown. It would be a great place for a PC reunion......in June not August, that is unless you want to share your S'mores with the Hell's Angels.