[tarmon8r]

Your talking about 20+ hours per quarter panel to do it right. Save your time and effort and forget about a "used quarter". Be sure to get a "CAPA" certified rear quarter panel. Its certified to fit, however its not always right. Im sure there are still NOS (new old stock) panels in the pipe line. The right way is not section in piece in the bottom. It should be at the C pillar about mid way up the hatch rear glass, and at the factory seam in the trunk and door. And if you have really bad rust, then the floor pan and inner quarter panel could be questionable. So you see, to replace the quarter panel could be a can of worms.
If you can even find a body man that will touch your car, they usually dont want to do "restorations", except for of course restoration shops or if you know someone. Most shops dont want to touch rust jobs.
As long as its not a show car, It can be fixed at a reasonable cost with some rust inhibitor, grinding, cutting, sectioning, bondo, and repainting with a blend. Good luck.