Throwing out the question as to which Toll Pass is preferred and/or accepted in more locations? Also which passes have a motorcycle happy mounting? Whether that be a sticker on the windscreen, transponder in tank bag. Thanks in advance for any/all advice.
I would look into the NC Quick Pass EZ Pass. If I am reading their website correctly, it is good in all states the EZ Pass is good for (15 states), plus NC toll roads, GA Peach Pass roads, and FL Sunpass EZ Pass is not for in these 3 states. There is a nominal charge for the transponder, but usually in rally mode the performance capabilities outweigh most costs considerations. YRMV.
An issue I see with the NC pass is that after 12 months of inactivity, they start charging a $1 per month fee until the account is exhausted. So if you live in a state where there's no tolls and don't go to states where there are tolls and you won't be using it other than the rally, you'd want to close the account so you don't lose your money. There are several EZ Pass states that charge monthly service fees, and some that don't (Illinois for one).
If you're planning on opening an account for the rally and shutting it down afterwards, monthly fees don't much matter.