I am not sure that there is a lot of Blues Culture or much of the sort of Country music that you imagine in downstate Illinois--and it is quite a long walk to the "Blues" States. There is a lot of music of all kinds along the Missisippi though, and you should look around to find the documentary/book/CD called "The Mississippi: River of Song" to give you some inspiration and a sense of where to go--

My worries for you focus more on the weather-- you will go through the heart of tornado country--and the cold, since you will likely be on the road crossing over a couple of seasons--also, I wonder how you're going to carry that guitar and a backpack--and of course, the guitar case needs to be watertight--