Check for rust on inner fender wells, door striker, and on the frame near the torsion bar mounts. Also check floor boards and spare tire well and sides of trunk near bottom of rear quarters.
Just be prepared to actually change the quarters to get the car the way it should be (and probably some other metal in the wheel well, truck extension, rocker)
Its do-able with some determination and lots of welding! not for the weak at heart!