Re: keypad replacement
If it's what I'm thinking, you'll need to remove the door panel.
Typically, you must pull the armrest assembly first, then the panel will pop right off. You'll have a sheet of plastic adhered to the actual door. You can cut a slit (or remove the section necessary) to access the back of the keyless entry pad. It'll likely be fastened to brackets on both sides (I believe the keypad would be pushed out from behind, or pulled if you are standing on the outside of the car). Free it from the brackets and you can unplug the keypad at the harness and to get the new one in, reverse everything.
Keep in mind- I've never done it before. That's just what I believe it would entail from an educated guess. It's not difficult, I don't imagine.