Good mod Ken, I like it.
My Compact II is too low to install a built in shower, which is one thing my wife is not crazy about, but your mod would allow me to place the shower in the pop up area of my trailer and 'wala' instant shower.
I have a couple of questions about the pump set up. We have been using the coleman pump for a shower while tent camping. This last summer I tried to use the pump it would not work. I took it apart and found the whole thing rusted inside. I had been submerging the pump end in a water container and not screwing it onto the coleman collapsable like it was designed to do. I think the water got into the pump somehow and rusted it.
I think you said you drop your pump into a warm water source to shower and then into the catch base to pump it out when you are done. Do you think rust will be a problem for you down the road or maybe my problem was the exception? I am invisioning mounting a small 12 volt boat bilge pump which is designed to be submerged that could be used the same way as the coleman portable. It could be pluged into a 12 volt outlet located close where you set up the shower.
A similer set up is used in boat showers with a small submersable pump connected to a water level switch mounted in a sump area connected to the shower. Any time water level activates the switch it starts pumping away.
I know the coleman battery
power is convenient but will it hold up over time by submersing it.
Thanks again for your mod idea.