Thinking of buying a 5th wheel caravan

I am thinking of buying a 26ft to 30ft 5th wheel caravan and Nissan navara unit.I am realy impressed with all the equipment that they come with ie A/C, water tanks, slide out sides etc, as we want to go touring in one for a couple of years it seems a good idea to have a bit of room. And i think they are better constructed with better kitchens and bathrooms and double glazing.

Has anyone had any bad experiances with sites not allowing them, or come across any problems with 5th wheeler's?