There was one member from Jackson Ms who had done some of this route...but she stopped posting several months ago. Others have done some of the Tenn portion. If you scan Natchez Trace, you might find some reports.
We live in Evansville if you need a place to stay between flights...PM Silver or me. We can also recommend Gilles Cycling in Evansville to pack and ship your bike if that's a good stopping point for you...it's about 80 miles north of LBTL.
We used to live in Nashvile before our riding days. Mississippi is flat, Tenn is rolling to hilly, Land Between the Lakes can have some very serious hills, but north of I-24 it becomes reasonably flat/rolling.
Let us know if we can help.
If you don't grow where you're planted, you'll never BLOOM - Will Rogers