This is a repost to try to include the images
Thanks to both Bills for the ideas. We have found the leak and it has been repaired. Turns out that the Corian Panel mount on the kitchen wall that backs to the shower is removable. It was held in place by double sided tape. Shop used a long flat piece of metal to slide behind the panel and cut the sticky tape. Once the panel was removed we found a access hole to get to the shower valve. It turned out the leak was coming from plastic 90 degree fittings that are screwed into the shower valve. The water lines connect to these fittings. I guess over time the fittings worked lose and starting leaking. Removing the fitting adding new Teflon tape and tightening the fittings fixed the leak. It looks like the leak has been going on for a while. I plan to reinstall the Corian using some wood moldings on the left and right edge. This will allow me to easily remove the panel in the future if need be.
I am attaching some pictures to show what happened.
Here is the panel that needs to be removed
With the panel removed you can see the shower valve access hole
Here is the valve there were water stains all over the plastic 90
Now I have to figure out how to reinstall the Corian panel without using double sided tape. I want the panel to be look nice but be easy to remove. Any ideas?
. A couple of day ago I noticed a wet spot on the ground under the Propane bay. I checked and it was dripping from the hole were the hard Propane pipe goes up into the motorhome. More checking and I found the area under the shower was soaked. The leak is not from the drain it is coming from the water supply lines. I took the cover off the Shower Valve and could see what looked like water stains on the pipe that goes down to the flex hose connection but that is not the leak. I opened the cover that hides the loops for the kitchen slide out but can't reach in to do any type of investigating or repairs. 
Linear Mode
