This morning, I talked to Dave, who runs the garage where my Jeep was towed.
Dave reported that he's been driving my Jeep around lower Montgomery County, but he's been unable to "recreate" the situation. And he thinks that the spedometer kicking out minutes before was perhaps just a coinky-dink.
So that's cool. It doesn't sound like I'm in for a major financial hit here. (Although anything over $20 will be a major financial hit for me.) It sounds like I'll be getting my Jeep back soon.
If they can't find the cause, doesn't that mean it can happen again at any time?
I'll try to remember to ask him what I should do next time my Jeep stalls miles away from home, other than calling a tow truck and getting it towed over to Dave's service station. Perhaps there's some clever automotive trick. Like holding my breath and crossing the fingers on my left hand while I turn the key in the ignition with my right hand.