RE: Leaking shower
I had a similar experience in my 5th Wheel. I found that water was running down the outside of the fiberglass shower wall and then running under the shower and across the floor where I could then see it on the floor. I solved the problem very easily as the water was leaking from inside the shower to the outside where I couldn't see it. First off I removed the hot & cold shower mixing fixture (chrome body with the hot & cold knobs) and then pulled it out about 2" . You will notice there is a hole for each of the water faucets (valves) and if there is not a good seal this is where the water from the shower head will run down into and then out onto the floor. Fill the holes with "Plumbers Putty", I also took Plumbers Putty and rolled it between my hands to form a long narrow rope like piece which I placed around the inside edge of the mixing valve chrome body. Carefully press the Chrome Body back into place and secure it. I forgot to mention that under the Chrome Body I had an inspection plate which could be unscrewed so I could get my hand behind the Chrome Body of the mixing valve to loosen the plastic nuts which hold it in place.
One word of warning, be careful you don't let the nuts slide down the hot and cold water lines, they would be a bear to try and get back up so you could refasten them in place!
Hope this helps, it sure did the trick for me.