door replacement

My sister has a 94 Crown Vic. She had a fire in the driver's door. The panel, switches and wiring are trashed. She's located a door (I think), and I was wondering if someone could give me some information in replacing the old with the new.
What year doors will work with her car? The new door has the key pad, and the old door doesn't. Will the keypad still work? Or is it run off of something inside the car? What's the wiring like? Is there a connector somewhere that I can just simply disconnect, or am I going to be doing a lot of splicing?
Thanks for any help.