Seeing your mention of Tennessee in September made me think of the last RV trip we made to the Volunteer State. We rolled into Pigeon Forge on October 15 and found out that RV sites were almost impossible to find because this was the height of the season to see the foliage change colors. We finally found a site. The next morning we hit out to drive around the park expecting to be knee deep in traffic. Cades Cove, usually a jammed scenic area, was practically empty. Ditto the rest of the park. However, when we returned at the end of the day, you couldn't get within a mile of the discount malls or tourist traps because of the traffic. Apparently saying you're going to see the scenic wonders means different things to different people. Tennessee, however, is a beautiful state. One place I would recommend visiting is Fontana Lake which is on the border of Tennessee and North Carolina. It is formed by Fontana Dam, the tallest concrete dam east of the Rockies.
Jerry