My husband and I stayed for 4 nights in June. It's massive, but there were only about 4 or 5 other RV's there. It wasn't until our 3rd day did someone come by to collect payment. Full hookups, close to downtown and $35/night. Trains are close and frequent.
This is a parking lot at the fair grounds. I'm sure it's fine for people traveling for the fair but not what I would consider camping.