Adding exterior shower

Just a thought? Could you somehow add extension to your low-point drains under the camper and bring them to the side of the camper. At the end, add a normal garden hose style threaded pipe so you can attach a hose and simply use a garden sprayer. This way, you have flexibility to move the shower head (sprayer) around. By disconnecting the hose from the extended low point drains, you now have your low point drains back in service. I've seen campers where folks have actually done this. Of course, you'll need to add a hot and cold faucet too. Still, pretty simple to do, and no drilling holes in the camper. And completely removable if you end up not liking it after all.