Water Containment and Shower:
Note that the Solo sprayer below is one of the most uniquely important items in the entire RV setup. It provides very efficient and effective running water for every purpose, inside and out. The link below is for the 2 liter version. I use the 1 liter version, which can be found in the related items on the linked page.
We don't use the buddy heater any more, but it's a popular solution.
Camping/External Sleep/Work/Fun Setup: