Folks, As i wrap up some home projects I have started looking at getting back to the cars. I have a 70 Challenger that has a golf ball size hole behind the rear wheel on the passenger side. It looks like AMD/Goodmark/Shermans, et al. have patch panel sections for that. However, the front has a worse issue. From the bottom of the rocker to about 7 inches up, the panel is like lorain swiss cheese. Also, the lower corner of wheel house is gone. I can fabricate the corner of the outer wheel house, but the quarter looks tough. The rust hits that lower character line and its about where the wheel lip starts to get its shape.

So my question is this, is there a decent patch panel for this area? Will a skin work to provide that piece (and I'd use the rear part to fix behind the wheel)?. I am trying to save the original quarter, though, in the long run the OEM style replacement may be faster.

The interesting thing is that the drivers side quarter behind the wheel is really gone, but the front section looks fine. I am guessing some dirt or debris clogged the drain on the passenger side that led to it rusting out faster.

Imo, as far as rust repair goes ,there is no way to guarantee the results are way a permanent repair. how the best result is to replace the panel if you rust in both front and rear of the panel and as you say the other side only shows one area rusted . thing about rust is , its not what you see that counts its what you don't see that matters. meaning the odds are greater that there is hidden rust that is just now starting to spread or will be soon after you've finished your body and paint.
If you have similar damage on both sides of the chances are that you should at least remove the panel to see what is happing between the panels. you be better of making any repairs while off the car or replacing THE PANELS. THE CARS IS FIFTY YEARS OLD. nothing lasts forever. just my opinion from making the same mistake many years ago.