The KOA in Union might be your best bet but 20 minutes to the listed suburbs is not happening. Hoffman & Schaumburg are the closest and probably 30 minutes, it can be another 20 to Arlington Hts depending on where you're going, and Wheeling is another 10 past that. We live right by Arlington Hts and Wheeling so we're very familiar with the area. You'll be driving around during the day and traffic can be a significant factor - these are all fairly large towns with a lot of shopping areas, you'll be on the expressway coming from the CG but after that it's going to be more surface streets with plenty of stop lights. Unfortunately there aren't really any better options - just be prepared to allow plenty of time to get where you're going and make sure you map it all out, can be easy to get turned around. One other note - there has been construction on I-90 for a while, not sure if it's going to be done this summer or not, could definitely add to the time required.