I have a 5 gallon bucket (was new metal "paint" bucket) with a piece of 1/8 pipe brazed in to base for a kitchen sink sprayer ( you know that hose next faucet the never seems to be used) .... I hang bucket it tree, and heat water in metal bucket either on camp stove or on camp fire and pour it into 5 gallon bucket, then temper it with cold water, usually have about 4 gallons of water enough for two people to wet down soap down, rinse down.... Usually I am out camping in more primitive camps but for privacy I use some black poly sheeting "clotheslined" to some trees for a shelter ( wife appreciates that) ......
Bucket could also set on TD roof and a privacy "screen" could be a hoop of metal tubing and opaque shower curtain....
Also found that a large plastic pan (bus tub from restaurant supply) to stand in, helps keep water for rinsing wash cloth and made a "duck board" to stand on when stepping out to dry off...
Duck board "nests" in plastic pan, next goes in is shower bucket, next is metal bucket (for heating water) next goes in Coleman lantern... Takes minimal space....
Think next version will be metal "sprayer tank" with kitchen sprayer hose and valve ... Not really keen on heating sprayer tank over flame but pressurizing sprayer vs. poring water in bucket hanging in tree has advantage.... Only issue is with sprayer tank is size vs cost and a large enough one (5 gallon) may not be available (really have not looked)...
EDIT TO ADD... Sprayer contraption could also be used for rinsing dinner dishes after washing....
ANOTHER EDIT TO ADD: This is what I consider to be ideal hose because of threaded fitting and on/off valve in spray head.... And its a general "hardware store" item....
Dale