I did mine last year.
3 bolts each end of the dash, 3 0r 4 screws along top of dash (pop the defrost vent cover that runs along the top of the dash off) , 1 or 2 screws/bolts accessed thru glove box, drop steering column and start easing everything back and let it rest/ hang by some wires on the seats. Then access nuts holding the box in from the engine bay side of the firewall. Remove the heater hoses etc. I had to access my A/c Condenser core which is in the same box, so I replaced the heater core at the same time. You are gonna have to have the A/C gas taken out and then have a/c recharged because you'll have to disconnect the a/c lines. It's a pain, maybe even more-so because of your cage. I had to unbolt my trail cage from the main hoop which meant leaning the windshield forward.
I did the job in about 6 hours, 2 hrs at a time over 3 nights which kept me from getting very P.O-ed about the whole cituation!!