I've done the Natchez Trace many times, on motorcycle and towing a travel trailer. It is 50 mph maximum the entire length, with only one stop sign that I can remember, no red lights. It takes about the same amount of time as driving from Natchez to Nashville on Interstates, but is much more peaceful and relaxing. However, don't do the Trace if you like to drive like a bat out of Hell, it won't turn out well. Lot's of interesting things to see and experience, if you like such kinds of history.