[ERASER5]

Pull a wire up the A pillar, use the visor hole just to get the wire up. Drill a hole where you want the wire to come out and fish it from the visor hole.

Some other things to consider. Only run the wire in the forward edge of the cab, all the way across is still good.. There is some kind of obstruction going front to back. Any area where cab lights would be mounted is good. There is room for more than 1 wire, for other stuff like cab lights, radio, powered rear view mirror.

Look up Texasfirefighter. He posted a vid showing how to blow a string up the A pillar and out the visor hole with a blow gun in less than 5 seconds. Seriously.