I got a EZ-Pass in NH last summer. One for the RV and one for the toad. The pass can't be moved from the car to the RV because they are diferant class of vieacal. I was instructed to put the toad transponder in a shilded envalope and put it in the glovebox so it isn't read when being towed. I looked up the fee schedual and when it is being towed it is billed as a trailer at a lower rate than when it is being driven as a car.
I would recomend you get a EZ-Pass because many roads are doing away with any place to pay. You might as well get the discount.
With out the Pass going across the Gorge Washington brige with the motorhome and toad was only $76.00.
I allso have a Texas Toll Tag.
Bill