Not everything in the National Park system is a park. There are actually a handful of National parkways. The Natchez Trace Parkway is one of them, and it winds its way 444 miles through Mississippi, Alabama, and Tennessee. You can drive the whole thing in a few days. Roadtrippers has a nice write up on things to do along the way and places to go. Not surprisingly, some of them I’ve heard of, particularly the Windsor Ruins in Mississippi.