You can save yourself some time and aggrivation if you don't remove the dash completely. you don't have to take out the front seats either. If you have unlimited time, these things do probably make it easier but its not necessary.
Disconnect battery, drop steering column, remove bolts along windsheild and down the sides of dash by the doors. remove the center console and the support braces under the dash behind it. You'll probably want to pull the HVAC control until ouut of the dash and unplug any cables going into the back of it. You'll want to check for one or two bolts hidden above the steering column mount and possibly behind the pass side airbag but I can't remember. Once you have all the dash bolts removed, pull the pass side of dash away from the firewall. Be sure to pay attention to wires behind dash and unplug ones that get too tight. there should be only 2 or 3 plugs you need to undo though. Hold the pass side of dash away from the firewall with a ratchet strap or a bungee or something.
Now you have to undo the bolt that go through the firewall and hold the hvac box inside the jeep. around 6 or 8 I think. you also have to disconnect the heater hoses and a/c lines (make sure a/c system is evacuated first).
Back inside now and you should be able to pull the hvac box away from the firewall and out the passenger side door past the dash.
The main thing is when you're pulling the dash away from the firewall, go low and make sure not to pull too hard on the wiring. you should still be able to move it 3-4" without encountering resistance so if you can't budge the thing, you've missed some bolts. Same goes for the HVAC box and also be careful of the wacuum line that goes through the firewall with the heater hoses during both removal and installation. you don't want to break it.