Maybe there's someone with more direct experience, but here's my take on it:
First, there's a lot of overlap with the TransAm. The purple (southern) route looks like it's the TransAm Route between Harrodsburg and Marion. It's flatter that a lot of the TransAm route, but you'll still have to climb out of creek crossings. I'd suggest you buy the TA map #10 for the section between Berea and Murphysboro, IL for the information on camping, detailed directions, and resources (including bike shops).
The blue route (where it diverges) is probably going to be flatter, since it looks like it's just outside the Ohio flood plain. Spring floods usually hit in April, and may run into early May. As a result, you can expect a fair few insects. September/October is usually drier, so if you have a choice, that'd be my recommendation.
The endpoints look like East Bugtussle and West Podunk. If you can't arrange for a shuttle from a friend, you might think about cutting the trip short, or making out-and-back loops. Paducah (Barkley) is probably the closest airport to the western end of the route, and it looks like Huntington, WV is reasonably close to the eastern end. You might also want to take the spur that goes up to Covington, KY -- that's where the Cincinnati airport is. (IMHO, we owe somebody a "thank you" for mapping out a route from near the airport down to the TransAm!) I'm pretty sure Greyhound/Trailways goes through Paducah, but I'd guess if you bus it you'd end up going through Nashville, so give yourself a full day to return if you use the bus as a shuttle back.
