We got an IPASS from Illinois. We have used it locally (IL and IN) and, on a trip east through Ohio, PA, NY and Mass. We had a single transponder in the motorhome and nothing in the toad. We have also been able to use it crossing into Louisville from Indiana (bridge toll) and on some of the Florida toll roads. I think most states rate a motorhome towing as a different class.
As far as route, you are going to pay for the convenience of using a limited stop more direct route. We thought it worth the cost.
BTW, Illinois does not charge a monthly or annual fee for the transponder and their web site makes it really easy to load your account as needed.
