I reserved a camp site last fall the day they became available. I could watch them filling up as I tried to decide on a spot and ended up just grabbing a spot I knew had room but was too close to a bathhouse just so I had something.
One thing to consider about traffic is that people may try to move during the day of the eclipse if the weather is clear in one area but cloudy in another. For example, if Hopkinsville, Kentucky is cloudy but the satellite shows clear skies in Nashville you might have a mess of people trying to relocate at the last minute.
