I have a 2009 Trail Sport, and much like you, Rayroof10, we noticed some soft spots. I got an estimate of $6000 to fix it. No can do. So I pulled up the vinyl, I still don't know where the water is coming from. the soft spot by the door and toilet were still wet, so I kind of suspected the toilet, but I can't see anything wrong with it. the other spot was on the driver's side, near the front. It is bone dry but clearly has been wet. No stains at all on walls or ceiling. Three existing penetrations for plumbing show a floor that is only 3/8", with about 2" styrofoam underneath. Is that all there is to the floor?