you may only need to take the lower dash out. i've only ever removed my complete heater box when i've had the whole dash out for other reasons.

having the entre dash out sn't the biggest deal anyway. just take off the steering wheel cowls, take out display to disconnect it, take off the bottom parts and the top part is held in with 3 screws along the top and one on each side at the bottom. just a few switches and stuff to disconnect, but put a cable tie that you can write on with a permanent marker on each one and it goes back together easily.