I keep a 50' glad hand hose on my truck. With a tire inflator and impact. Works great. I also keep a blow gun on hand - great for blowing the dog hair out of my cab, cleaning my HVAC filter panel (AC console has recirc filter), and blowing the dust out of my habitat, etc.
I have run a 3M DA Oribital sander, die grinders with pads and wire wheels, etc. Very useful. Remember to put the truck on high idle if you are using something that needs a bunch of air. And service your dryer appropriately if you are running tools a lot and not just the intermittent compressor operation for the service brakes. The more the compressor runs the more water it will condense and the more often the drier will need service.
The pressure will be whatever you compressor unloader is set to. Usually and per the spec it should be 125 psi.