I am renting a compact SUV from Hertz for the RTR. Bob has now said more than once that the frontage road must be taken to get to the site- and that it is a super rough road. Does anyone know how rough and whether it might be worth risking in a rental? Any info is appreciated. Some people would probably rather risk their own car but I can't do that right now and I don't want to return a rental car with damage. Thanks.