I have one toad that puts me overlength, and one that keeps me at 65'. Like George I have never been bothered, but have spoken to several Prevost owners that have been ticketed. The thing consistent with those that have been ticketed is they did something to draw attention to themselves such as speeding. One owner I spoke to got a substantial fine in SD, a state that we know will cut recreational vehicles a substantial amount of slack. When we had the rally in Spearfish the state police weighed our coaches and then met with us afterward. They were very much aware of how many tourist dollars flow into the state and knew that RVs are to be below their radar. The Prevost owner I spoke to admitted he was speeding and maybe the overlength fine was actually a blessing because he probably did not get points.
With the exception of CA I suspect almost every state will look the other way at overlength rigs unless the Prevost driver is speeding, tailgating, or otherwise doing something a cop might find objectionable. Weight is another issue. For many years Ohio has been keeping coaches that exceed the Ohio axle weight limits off the Ohio Turnpike for example. They apparently have sensors in the ground and if the coach exceeds their limits it is denied access. I am not aware of any fines as a result however.