I'm not at home on my computer where the pictures are, but I'll try and describe the set up I used for years.
I used some steel tubing that slid inside the crossbars of my Yakima roof rack, that I could extend out of the roof rack. They would be used to hold up a hula hoop that I had clipped two overlapping shower curtains to. I made a thin pallet type floor for the bottom of my roof rack basket that lifted out and set on the ground to become the shower floor.
At first I used those solar shower bags for hot water, but found my shower became real popular with the females in our camping group and heating enough water to keep up with demand became a problem. I found a solar bag would provide enough hot water for two people if they were conservative with the water. But the demand quickly got our of hand
So I ended up building a heat exchanger that tied into the trucks radiators circulating hot water. Used "T" fittings on the trucks heater hoses to circulate the engine coolant through the heat exchanger.
Ended up building a cold water mixer into the plumbing to keep from scalding the folks in the shower. All water was circulated out of a 5 gallon water bucket with a 12 volt water pump that was plugged into a trolling motor type electrical plug mounted into the back bumper. As long as the water held out it worked great. I soon found the best way to keep up with the demand was to require each person using the shower to bring their own water. Or make them fetch a 5 bucket full if they wanted a hot shower.
Ended up hanging a hook off the hula hoop tubing to hold their dry towels on the outside of the shower curtain. And a hanging soap dish thingy inside too.
The biggest drawback was the water puddle left around my truck camping area. I solved that by parking on a slope so water drained away from my truck during shower time.
The heat exchanger was nothing more than an empty propane can that I ran a coil of copper tubing through with 2 water fittings brazed to the propane can for the radiator water to circulate through the small propane can.. And two barbed fitting for the copper tubing. I cut the end off the propane can and drilled the holes for all the fittings, added the copper coil then brazed the end and fittings on the can.
It took up very little room under the hood and was mounted to the fender well with hose clamps and a simple bracket.
Never failed to work and was a great thing to have handy.
