Here's the rest of the unbelievable saga concerning my wife's 1988 Volvo 240 DL.
As you might recall, I had finally set the alternator ground correctly. So the following morning, the most nearly perfect woman set out again for Portland. She got to exactly the same spot where the car died previously, and ..... not poooof, but WHOOOOSH! Smoke billowed from beneath the car! She stopped, and found transmission fluid pouring out on the ground. She luckily had some more in the trunk, put it in, and drove right home.
Now, I have to admit I was quite worried that driving even a short distance with low tranny fluid might have ruined it. I was also quite worried that she might have seriously reinjured her ankle when she kicked the fender. (Yes, the recent car woes are just the capstone on a winter that's been hard for many reasons.)
I was able to Google some Usenet discussions on repairing transmission cooling lines, and found that some had had success with EFI fuel line. If you ever need to do it, just make sure the inner diameter of the reinforced rubber tube is the same as the outer diameter of the cooking line. Cut off as little of the cooling line as you can get away with, and extend the rubber line at least three inches along each end of the cooling line. I used four clamps on each end of the hose, because wotthehell clamps is cheap.
So far, so good. It seems the tranny fluid was never down more than about a quart, so nothing too ruinous occurred. No leaks yet, either. Just a ruined vacation for my poor wife, who most definitely deserved far better.