She's a beauty, CBean! And A/C, too!
I picked up mine the same weekend. All I was looking for was good bones, too.
It had the classic corner leaks but the interior was nearly mint except for the water stains in the corners.
I didn't look to see if there is a prescribed fix for the butt joined corners but I took the corner moldings off and pulled back the (side) roof molding for about 12 inches. Then covered the corners and about 6" of the roof with Peel & Seal that I cut into 3" wide strips (cut the 6" wide roll in half). I reinstalled the moldings over the Peel & Seal and replaced all of the screws I removed with stainless sheet metal screws.
I had looked at a couple newer fixer uppers in my price range. They were rubber roof models but most of the rubber roof was missing! That's when I decided to concentrate on a solid older model!