The Cook County Forest Preserve RV sites in all three of the RV campgrounds accommodate coaches up to 40' but no water at the site. The Palatine location has a sewer connection at the individual site.
The problem with being farther out at other campgrounds is that you'll have to bring Metra into town. Metra is a scheduled commuter rail service and the trip will be 60 minutes or more depending on the line. It also doesn't run near as often as a subway.
The Forest Preserve campgrounds, even though they may not have full hookups will allow you to skip the Metra train and use the Chicago CTA train (the L) instead. These are "subway trains" that run much more frequently and are much quicker and cheaper into town. You also have CTA and Pace bus options for other destinations not downtown. You can buy a visitor pass that allows unlimited use of the CTA subway and bus for a certain number of days.
It may exist but I've never heard of any campgrounds in Chicago with tours like Cherry Hill has.