Other than ripping everything off, only issues to tackle are if the AC bracket needs modified to provide support to the power steering pump when the pump is removed, a flat metal plate to cover the hole in the firewall, and if keeping the heater assembly, finding a donor to replace the heater box and heater controls. If you can find a non-AC donor, you can probably get the correct non-AC power steering bracket from it as well.
At least thats all I can remember off the top of my head.
Edit: At least on the '81-91 K5's you can use the non-AC passenger kick panel manual air vent setup. Can't on the drivers side of an AC truck, unless you cut the hole.