There is a private campground in Joliet Illinois. Martin's campground is about 10 minutes from the train station (metra) which will take you into Chicago. I have family in the area and we always we stay at Martin's campground. It is $35.00 a night but it sits on I85 and it is noisy. Honestly it works for us. It has a bathroom facilty ( not the nicest but functional) and WiFi. The owner is very nice and it is 1/2 mile from the chicago land Airstream dealer.
Brian & Adrienne