I think you need to forget about the elevation change and start basic trouble shooting. Check to make sure the choke is operating, can you see fuel squirting into the carburetor when you operate the throttle? How fresh is your gas and how much is in the tank? Check to see if a fuel line may have gotten pinched/crushed when the car was tied to the trailer. If it was running fine when you loaded it, I would not mess with the timing. Yes check all your wires.

Pat