My neighbor is really into his offroading four wheel drive truck and does a considerable amount of camping out in areas without amenities and he has a very impressive hot water shower setup built right into his truck which in our case would be the tow vehicle.
http://www.hotwatercampingshowers.com/

It comes as an entire kit that you install onto the vehicle. He has used his for many years and says that he has never had a complaint about it. This is a fellow who abuses everything he takes out with him so that is a fairly strong recommendation.
I myself will eventually get my VW/Westfalia Transporter project sorted out and will use it as a tow vehicle. I'm not certain yet if this system will function with an engine that only uses oil for cooling but I hope to find out soon.
I believe that this along with your flavor of privacy and flooring contraptions would really be a wonderful addition to your experience. Since it would be preinstalled you would reduce the amount of material to carry along with you inside your tow vehicle or trailer.