That's one of the big advantages to having air brakes. I just used an air cut off wheel powered my by skoolies air system the other day. I also use the air to open and close my front door, as well as the flaps that surround the jacuzzi.
One thing you'll notice is that the a/c on your bus doesn't produce much cfm, unless the engine is really revved up. My compressor spins at about half engine speed. Since the engine already idles about 600 rpm's, it takes a long time to create pressure at idle.
I've put air in skoolie tires, car tires, ran air tools and launched potato's from my pumatic potato launcher with the air supply from my bus.
It's been recomended that you install an inline filter to help keep any of the gunk from your air system from entering the air tools/lines.
You can easily install a "T" into one of your air tanks using standard pipe threaded connectors. Another advantage is that if your bus won't start, and you absolutely had to move it, you can use a compressed air supply to charge the brakes on your bus.
Quis custodiet ipsos custodes (who will watch the watchmen?)