Remove rear seat and metal panel. Remove the rubber seal held in by screws in the door opening. When you remove the metal panel by the seat, you will find MANY 1/2" bolts holding all sorts of stuff in the quarter area. Photograph if possible. The first trick will be removing the regulator. It unbolts and slides out of the tracks. After that, it is just removing all the stops, etc, that hold it in . Removing the tracks probably is necessary, depending on skill level.
Remove the window only if you have to. To paint, just remove the lower stop, and it will sink below the body level.
Most of the time, the problem is not the window, it is either the rollers or the mechanism (or both). Ensure the rollers are not broken, tracks are greased, and regulator works before pulling the window.
If you do pull the window, replace the weatherstrip on the window $10 2 minutes, and on the body $8, 5 minutes.