Contacting the CHP and DMV is a good idea. Only if the OP is willing to go with their answer. Sounds like they are wanting to go a certain (safest) route. Rental places aren't gonna help you with this because if they tell you one thing and then something happens, you will try to hold them reliable. I don't blame them.
You can always just follow the rv in your own car where you have it set up already for proper seating. The. You will have a car to drive. Might not be the most favorable option, but at least you will feel good about it.