It looks like there is a race on at the Napierville track but possibly access on the Saturday - not quite sure how to read that.
http://www.napiervilledragway.com/calendar2006.htm
That weekend would work for me, though I imagine booking accomodation would need to be done fairly quickly with the Jazz festival going on.
Can't really speak from first hand about the track or accomodation though, as I've never been to either.