About half way between Geneseo and Moline there is a lock and dam site on the Hennepin Canal that allows camping. Normally, it's $8 per night, but free during the week for Illinois seniors. There are several sites along the canal with similar camping. Also, the website for the canal says the parking lots at canal sites are open 24/7. I don't know if that means you could park an RV or van there overnight without being considered camping. There are several of these sites along the canal that have parking areas, but, technically, no camping.
