We talked a bit at RTR about our rigs. Reading at your site reminded me that I forgot to mention a few items.
My Sprinter conversion has a 24 gallon water tank transversely mounted beneath my bed. The tank can be pressurized by a small if pump, the tank is plumbed to a small sink and to an outside shower between the rear doors. I use a product called Scrubzz, fancy wet wipes from Amazon, to extend time to my next shower. In desert remote camping I can stay out approx a month.
My Airhead lasts about as long as well.
The shortfall in my design is lack of storage, as I now carry several plastic tubs on one third of my bed and several more stacked and bungeed behind my passenger seat with food stuffs to stay out for that month.
It was very nice talking with you, hope to see you again down the road.