The toll booth are wide enough to get a semi through, so your RV should fit. If you run through the "Open Road Tolling" lanes without an Ipass or EZPass transponder, then you have to pay online within 7 days or you will get a ticket in the mail.
If you are coming across on I-80, be aware that there is construction (as usual) between Joliet and I-39. Most of the time it moves pretty well unless someone messes up in which case it will back up for miles.