I rode with a with another guy from Grand Rivers, KY to just into Alabama and back in 2005. Most of this portion was on 2 Parkways with no commercial vehicles. There were campgrounds along the 2 parkways that as I remember were reasonably priced. We camped at a motel in between the parkways, I believe it was the Southernaire. It was located about 25 miles north of Waverly, TN and they charged $5 a person with a shower. There also was a restaurant at the motel. We rode in heavy rain on the way back north and stayed at the motel, rather than camping. I don't think the price was too bad.
There were no towns directly on this portion of the Parkways but there were towns just off of them. We did not camp in any of these towns but did go off for lunch and groceries. The riding on the Parkways was very enjoyable, much like the Blue Ridge Parkway. There were rolling hills in the north and little traffic. As we traveled south the parkway became less hilly. Like the Transam in Kentucky, the roads in between the parkways had some steeper climbs and some loose dogs.
The only city park campgrounds that I see listed on the map set are in the section north of St. Louis. On a different tour in 2005 I rode a portion of the Great Rivers in Illinois and Missouri. Typical of most ACA routes, quiet roads through small towns. We even had a cyclist come up to us in a grocery store in Cape Girardeau, Mo and offer us a camping spot in his yard and a shower. We stayed in a couple of motels in southern Missouri and Illinois small towns and they were priced very reasonably.