Short of that, the Williamson County Airport, in Marion, IL, is currently served by Cape Air, which connects to St. Louis. They have four or five flights a day and should be pretty convenient for you. When you book an airline, just plug in MWA as your destination. You will skip a lot of hassle in St. Louis.
FYI - it's about a 2-1/2 hrs. drive from St. Louis Lambert field to MWA.
Rental cars are available for a good price: http://www.mariontoyota.com/rental/showroom.htm?tcdkwid=23043688&tcdcmpid=20828&tcdadid=6489531836
Or here: http://www.carrentals.com/
The event will be held at the Midwest Aviation FBO, right under the control tower.
