Christmas Break is here and I finally did some cleaning out of the Vandura. There was some Mystery Goo in the passenger side door well, which looks to be polyurathane varnish... My theory is that a quart of the stuff sat on the dash in the sun for a decade or so and the UV caused the container to fail.
Thanks to Dave the Car Guy, I was able to effectively track down new front door latch mechanisms, new, OEM, which I will replace. I hope to get the engine running and steam cleaned before Break is out. My first goal is to get the thing to move under its own power. The three-on-the-tree gearshift is totally inoperative.