I did discover that my water leak is via the slider. Since I left it out 24 hours a day (full time), rain was often leaking past the rubber flaps, etc. I heard from a couple of dealers that the Coachmen Spirit of America units weren't intended or designed to have their sliders out full time (which is a shame).
I've also discovered that the water damage includes the 2x4 that is located at the bottom of the aluminum siding, and the plywood flooring that runs under the bedroom window and also under the slider area, so the slider will have to be removed to replace it. The flooring is also soft toward the kitchen side of the slider, so the repair will definitely be more costly and difficult.