I went along with Robdirt and Nanohicup a couple years ago. Wasn't blown away with the route because of so much recent pavement but still had a good time and was glad I went.
Seems Sam Carraro has changed it up a bit since then and I'd like to give it a go again.
He's created 3 trips. The Trans American Trail. Shadow of the Rocky's and Mississippi Hill Country.
If anybody else is interested, let it be known. I'll order the north/south routes (507 miles total) and we'll figure out a date to do it sometime in the future.