I use a couple of pieces of hard, card stock paper. Place it inside the door openings and trace the door opening on it. Cut them out slightly larger than the opening. Once ready to paint, I place a handle out of tape on each card mask. Slide them into place in the door opening and you are ready. Tape off window glass and paint. You may get a little overspray in the areas of the door where they meet the floor, but this is easy to touch up. Hope that helps.
Gino P. Quintiliani - Field Artillery - The KING of BATTLE!!!
Check out my Gallery: https://app.photobucket.com/u/HeavyArty
"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." -- George Orwell