I did this trip 4 times last year.
The first gas station in KS from OK, has E85 so you should make that, that should get you into kansas city, MO where you can E85 again, then you will be in IA where E85 is plentiful.
I used this site:
http://e85prices.com/e85map.php
Good luck, any link to the car I might of seen it while I was down there.