I started with a used, non working, 3gal 110V air compressor that I found on CraigsList for $20. This had everything I needed; like a pressure relief valve, pressure switch, drain valve, check valve, and was the right shape configuration I was looking for. (long and skinny)
Once the 12V DC compressor was mounted and attached to the tank. I mounted the whole assembly to the truck bed. The tank has integrated rubber feet, which I used as part of the attach points. Now the tank is semi 'rubber mounted' to the truck bed.
I ran a fused 12AWG wire pair directly from the battery to the compressor. But I also ran another pair of wires from the cab, to the compressor to be used as remote ON/OFF from inside the cab. The remote switch powers an automotive style relay, which allows the current to the DC motor of the compressor. See the full electrical and air line schematic below. The schematic shows additional equipment that supports air horns, but I do not cover them in this instructable.