I mounted 1 in. larger wheels, then used a drain extender like HD's sku #1000053233. I mounted the valve end to one of the leg struts and added an elbow so it would shoot down into my drain pan.
The red HF compressor has the drain hole located off-center. One must tilt the compressor to drain the tank. Unless the tank is "parked" at an angle, an auto drain would be ineffective.
Thanks guys. I may have to go with Ken's idea as the bottom of the tank is pretty close to the ground so I was concerned that there would be a clearance issue with just an elbow and piping out the side.