Road information

Thanks you all, great advise, I think at this moment we are going to take 550. Our RV is a 39 foot 5th wheel with dual axels and a 2013 model, Truck is an F350 Ford 2013 model so I'm thinking brakes should be no problem. Only thing that concerns me is equipment failure. Not sure what an exhaust brake is so I assume I do not have one?
One more question is about speed limit? and what do you do about backed up traffic if there is not turn outs? Third week in September is targeted time?
Thanks again.