Oh yeah, free AC, gotta' love it.
FWIW, I started at about the same place on my Starcraft, had leaks from the aluminum roof into the framing. The top sill plate was pretty much gone for 50% of the frame. I could put my arm through one spot on the aluminum siding. About 30% of the rafter ends were gone on both sides.
After frame repair was completed, I caulked the top edge of the framing and stapled the aluminum roof back down. I then sealed the aluminum trim edge to the roof. After screwing the aluminum trim edge down, I put in a new vinyl screw cover and thought, "that oughta' do it!". Not so. I had a few top side leaks at the edge of the roof. My theory is that it was from unsealed screw holes that fastened the edge trim. I later covered every joint and the trim edge with Eternabond tape. That has stopped the leaks.
I now do a blower test about every other year to expose any failed sealer or spots that have developed to offer an entrance for water. The Eternabond has never leaked but I have found a siding leak here and there. Once you do a lot of work repairing a water damaged trailer, it makes one fairly proactive about keeping up on the sealing.:)
Good luck with the repairs, it appears you are skillfully getting things done.
