Campground, the nature trail, and the Mississippi river within walking distance right across the street from the airport. If you have personal transportation with you, there is a good restaurant (The Riverview Lodge) 2.5 miles down the trail. There are no longer any on-field transportation options.
2008: Flew in on a Sunday and terminal was locked. Supposedly there is a courtesy car but could not be accessed afterhours. Also, the closed Savanna Army Depot is neat to see from the air. Pilot lounge locked after hours, dealership will rent car for $37 / day.