Once again, it's been a lot longer than planned since the last update.
Since then, I cleaned, de-rusted and re-painted the sheetmetal heat ductwork. I media blasted the worst of the rust off the parts and then soaked them in B'laster Metal Rescue, which is their copy of Evaporust. The stuff is nice because it won't eat the metal once the rust is gone, but it takes a long time, is rather expensive and doesn't last as long as one would hope -- I went through 3 gallons before everything was clean.
Turns out I had already scrounged up and stashed away all the sheetmetal needed, except for the flat-ish guide plate that goes above the shift rod. Fortunately, AA had new repros in stock, and it needed only minor tweaking to fit (had to move a couple of holes).
I also connected the heat control cables and the hoses to the body ducts.
Here are a couple of pics of the finished job:
