Finally got around to figuring out how to install a generic RV shower on my van. I will be happy to explain any questions the best I can but this will mostly be a step by step picture thread. It ended up being very easy to do and looks great, like it was meant to be there.
Here is the faucet I used, I am sure there are some slight size variances between different styles, this one worked for me and comes with 2 keys.
Here is the process:
Remove 4 screws from behind panel and it pops out.
Cut back of faucet box off 2.5" at top kept, 1.75" at bottom
this saw worked better
I used the back portion to line up the faucet holes but the stock location didn't work, it sets it too low and in the shallow part of the box, I had to flip the faucet upside down and drill new holes higher so it would sit in the deeper part and that just barely fit to shut the door.
(don't make the same mistake)
Back on, this pic shows the 4 bolts to remove the whole insert as well as the plastic I had to put to patch my lower messup holes
Tapping into hot water:
And cold water:
30" stainless lines with shutoff valves and push on pex connectors (easy and smooth to use) 1/2" connector on end of line for faucet, 3/8" for shutoff valve:
All hooked up front side and back: