I just did this job 4 weeks ago. Here are a few more tips.
First off, I don't have AC.
There are 5 studs in the back of the plastic air box that contains the core that go through the fire wall with 7/16( I think) nuts. The studs may turn out of the box, rather than the nut coming off of the stud. Take care when removing the dash and lifting it over the steering column so as to not crack the windshield :doh: . I found that the bolts holding the defroster manifold to the firewall had been overtightened somewhere along the line and the ears were broken.
If you have anything else you want to do that requires pulling the dash, now is a good time to do it( if you can) before putting it back together.
There is a thread on here somewhere with a step by step that I used as a guide.
Also, you don't need to drain all the coolant, just the bottle and the lines to the heater.
If your core leaks like mine did, it drained itself on the floor.
Took me 6 hrs, taking lots of breaks as I was outside in 10 deg. weather.
Good luck!