Get enough gas that you can make it clear across Illinois at the moment.  The Amanas that were mentioned is a good stop if you want a feast.  If you want a place out this way to make a longer stop or an overnight, Leclaire Iowa just this side of the Mississippi is great.  Fantastic restaurants, Bill Cosy and riverboat museums,  a distillery winery and microbrew all in walking distance, and lots of cool shops.