I have not done this but to save money, start at a junk yard. Strip the insides of all four doors. Spring is here and bees will start to nest soon. Working inside the doors is a major hassle. The access openings are not made for big hands. You will also drop several screws/nuts inside the door so bring a magnet on one of those flexible do-hickies that can be found at Dollar Stores. It will not be a quick job at the Junk yard or after you start to upgrading the doors. I would leave things alone, that way your doors & windows will always work
If you still choose to upgrade then you will absolutely need the wiring schematics from Haynes or a FSM. Good Luck.