Misfire at cruise, popping/afterfire at 3000RPM

Well, I certainly am grateful for all the advice given, and I hope it never seems that I ignore that advice. I was getting ready to do some electrical troubleshooting as suggested by @67Dart273 and then go from there, but I found the tattered wiring and rotators on the valves, so I decided to just dig in and get going.

I'm not shy when it comes to documenting problems with the car, because hopefully my experiences can help others in the same situation.