It's a pretty major undertaking and it seems to come down to a few dedicated individuals, who do a lot of recon to put these things together. I don't know exactly how long, but Sam Correro states that it took him years to create the TAT.
While it's challenging to link dirt and gravel roads together into a cohesive and "meaningful" route, it's getting harder and harder to find roads that aren't covered in tar. Try as I might I'm hard pressed to find them in Kentucky.
As far as routes in other states are concerned, it's one of those things where you may come across a gold mine (someone else's route=labor of love) or you'll have to go out and make one of your own. Either way it's a win-win. Welcome to the forum.
