Such great suggestions--thank you!
Yes, I'm assuming the black spots are mold, so I'll need to deal with that before really getting into the repair.
As a side note, we noticed the strangest thing this afternoon.... As I've mentioned, there's no gloss on the trailer and I plan to use Zep (which I've seen recommended here) once I got a handle on everything ELSE that needs to be done!)
But as we pulled into the driveway this afternoon, we could see a "circle" about 6-8" in diameter to the upper right (driver side) of the large front window. This is the first time it's shown up and (as usual) we're clueless. Wayne said that maybe it had been patched before, or maybe at one point something came out of the front. We really know very little about its history.
We heard that Scamp
sold some empty "shells" to the military to be used as a mobile command center in the mid-1990s (this is a 1995 model), and the person we bought it from had gotten it from a construction company that used it as a mobile office. We can see a faint discoloration on the door and assume it had an "OFFICE" sign stuck on it at some point.