Nice to read your comments!
This forum is a great resource, and they is no substitute for making lots of mistakes.
And boy, talk about hats - I have to wear so many different ones through the course of this project, right now hopping between electrical troubleshooting and autobody prep work. I know I'm certainly no pro at any particular category of vehicle rebuilding, and hoping that the overall combination results in something decent. Right now, with the eternity that the filling, sanding and priming is taking, I wish I had the skills to bring the bare sheet metal a lot closer to perfect before laying down the plastic.
Well, here's the update: I've been cursing at my wiper motor a fair bit, and can now take it apart in milliseconds. With some help from a guy today, I now have a much better grasp of exactly how it works, and there indeed seems to be some problem, at a minimum, with the wiper motor.
I can get the motor to turn the arm, but when it gets to the end of the electrical contact sector on the main gear, for some reason the other contact (of the three - my motor also has three brushes) does not work to reverse the motor the other way. I looked really closely at the contacts going to the face of the gear sector plate, and one of them was a little frail at the end, so I suspect that the wiper motor is done.
So, I'll be ordering a new one tonight. It's also possible that the wiper switch is not working properly, so I've ordered a new one of those already. The wiper relay makes a noise and appears to work. So, the only possibility remaining, after i get a new motor, switch, and relay, is that the wiring between them is not right. We'll cross that bridge when we get there.
I've been plugging away at the body panels and they're getting really close now. One you get a complete coat of primer-surfacer on there, the flaws just leap out at ya, so the subsequent finishing stages seems to get longer and longer. I'm doing my best this week to wrap them up so I can move onto the main tub and upper cab piece. Here are some picture from the past few days: