I love troubleshooting. The first step is to figure out which system is really giving the problem. From the sound of what happened, my money would be on a problem with fuel delivery or ignition.
Sounds like you've pretty much eliminated the fuel system. (OK, you could still have a carborator problem, but from the sound of how it died, I think you can move on)
Pull the coil wire off the top of the distributor and hold it close to a good ground and have someone spin it over. You should have blue sparks jumping from the wire to the ground . . . if not, you've got an ignition problem.
If you have no spark, then you need to #1 make sure you are getting power to the coil (pretty easy . . . turn on the switch and pull the power wire to the coil . . . an jumper should be running off of the same side of the coil to the idle cut off on the carb . . . when you plug / unplug the wire, you should hear the idle cut off clicking. If so, you have power. If not, you have no power OR, maybe you have a bad idle cut off . . . but again, from the sound of how this all went down, I don't think the idle cut off is an issue.
No power . . . could be your ignition switch, a broken or loose wire somewhere, etc.
Got power to the coil? Like KC said, check your points . . . that's probably where your issue is. Could be a bad coil. Could be a bad condensor . .. .but more likely a points issue.