You got some great information on this thread. Here are some other things to do and see while visiting Memphis:
National Civil Rights Museum
Sun Studio
Gibson Guitar
Mud Island and Museum
Our favorite BBQ is Central BBQ. Try their BBQ nachos and ribs - yum!
An alternative to camping in the Memphis area is to stay in a COE park - Hernando Point which is just across the border in MS. It is about a 30 minute drive in but more like camping and less like an RV park.
Enjoy your visit and dress for hot and humid weather!