That's a good idea to hide the air tank in the quarter panel. However, my truck has a flatbed and I have underbody tool boxes so I'm running out of room to hide the air tank.
I'm completely restoring this truck so the wiring has to go. The previous owner cut, rewired, used household wire, etc. to make repairs. That has caused lots of electrical gremlins that make the truck unreliable and frustrating. Rewiring to a single large tank in the rear just makes sense for this application.