[LS short box]

Again my.02.
Looking at the current pics I would pull the fenders and doors and go down to bare metal.
Then using a dolly and hammer or dent puller get them close. Then a couple coats of filler sanded down to nothing. Then a coat of spray poly sanded down to nothing. Then two rounds of 2K sand able primer. I've good luck taking parts to to local body shop and having them spraying them with primer as needed.
Then bolt them back up and see what the look like compared to the quarters. Then work the quarters to match the doors. Or you could do just opposite and do the quarters first.