The more I think about it, the more I think you guys are on the right track w/ fuel vapor.
It was hot as Hades out; perfect conditions.
The wires that burned weren't powered up - the car was off.
The stuff that could have been shorting doesn't appear to have been. This is backed up by the battery still having a charge two or three days later.
Well, I've ordered a new set of Firecore wires from Rick. Now maybe I'll just have to buy a barbeque to cook the pork shoulder and keep the truck as a truck.
Hopefully, I'll have the following results...
-Bill