When i hod mt bronco I changed the manual windows to automatic and also the locks. I got a kit from JC Whitney. It all still worked when I wold the bronco 5 years later. I bet if you found doors with automatic stuff in them and swapped them for your doors this would probably be easier. You would just have to be sure to get the electric box that is under the dash also.
I did this with all aftermarket stuff. I'll be posting all the pics and stuff in a couple weeks, I'm waiting for my new door panels to get here to show the finished product. It's not hard but it's not easy either.