See if the library has copies of George List's book, Singing About It - Folksong in Southern Indiana. You can also get it used online from a couple of sites. It's a wonderful collection.

If you're anywhere near Bloomington, the folklore department at the University ought to have MANY resources - it's one of the top folklore departments in the country and specialized in folksong. (That's where Joe Hickerson, among others, went.)

Lotus Dickey was an Indiana musician. His songs are not exactly traditional, but are amazing!

Good luck!

Dan