Just another option, if you like hot weather a whole bunch. If you can figure out how to get to Staunton, IL., you can take trails all the way to Kansas City, MO. for 95% of the way.
Three trails will do this: Quercus Grove, Katy Trail, Rock Island Trail. Sure, a couple gaps and some road riding, But trail for the most part.
Here is a thread I started about Rock Island and the Katy Trail:
http://www.bikeforums.net/touring/10...rail-news.html
Madison County Transit in Illinois (link to map)
MCT Trails Map
I'll let ya research the Katy trail and the Rock Island, lots of info on the web.
One more tidbit...mostly unpaved, fine ground limestone smooth on a dry day. Wet...could be an issue especially with certain tires.