don't do it!
removing the door eliminates recirculation mode. from then on out the truck is sucking air from outside to cool as opposed to recirculating the cold air. a/c will blow but not nearly as cold, know this for a fact as the door in my dad's truck broke completely and fell out.
replacing the recirculation door requires removing the entire dash assembly, as tough as that sounds, is not that bad. took us 5 1/2 hours from start to finish - after doing it once, could probably cut that time down drastically.