Bingo, almost. Neutral didn't cut off the gas, but I should have put it in neutral and turned the car off approaching an exit ramp and coasted the rest of the way. That was the right answer, but while I worked through all the scenarios in my head for about 30 minutes once I saw what was happening, that one didn't occur to me until the next day. And I thought of some crazy stuff...
1. Drive for like 5-6 hours into Virginia until I ran out of gas
2. Call the cops and tell them to put down the tire shredding ropes
3. Try to roll the car
What I was really nervous about was somehow getting a cop on me (for a tail light out), and getting in a high speed chase I couldn't get out of.
It was real late at night, so my final answer was that I would go ahead and try to exit, and just stand on the brakes with all my might, and hope to slow it down enough that if I couldn't stop it, I could turn it into a telephone pole or the side of an embankment if it came to it. My big fear was that I would come off the exit to a line of cars at the light, and I wasn't going to hit another car going fast, so I was seriously planning to roll it or put it in a ditch if it came down to it. It was late at night, so I wasn't too worried about coming up on a line of cars though.
As it turned out, I was able to bring it to a stop standing on the brakes as hard as I could, and pull it into a shop to leave it. But the obvious answer of just turning the car off never occurred to me.