Darn POS, RV'S can't keep water that's supposed to be on the outside out, and water that's supposed to be on the inside in. Just started a weeklong trip & threw the kid in the shower and there's a ri...
Look on the other side of the wall from the shower. In my trailer I had crawled into the storage area under the rear bed (don't ask) and there was a panel in the wall with a screw holding it up. I removed the screw and panel and the underside of the tub and drain were right there. Maybe your trailer has a similar setup.