Recently, at one of the autocross events with the mustang club, a couple of guys were running a rotax dd2 kart. I talked to them a bit because I just purchased a kart. If you know the route to take, it is smooth enough from what they said. Although he did hit one spot that lifted both back tires on one run. You would defintetly want to learn the track. Problem is that you only get between 3 and 6 runs in a day. Mustang club is nice because you get basically 1 full lap before timing starts and 2 full timed laps per run. SCCA does one full timed lap. Either way it makes for a very long day with only minutes of drive time.
None of this info is too relevant though. They just announced recently that the track was sold to alliant energy and this is the last yr it will be utilized for any sort of racing. Its a bummer because we use the track to get baselines and comparisons for changes made to our cars. I also planned on taking my kart there at some point.
Im located in Des Moines area and plan on making it to 61 kartway and also there is a track north of Kansas City(KC Karting). If you are in Nebraska(?) you also have a place in Hastings to race.