I have tackled this issue myself on a 70 GTX.
I have ended up replacing EVERY panel including both rockers and all 4 door posts!!!
I have NEVER done any body work before I started this project.
My mind set was that I needed a hobby so I have remained calm and I have the advantage of a great friend who builds cars for a living letting me do this in his shop under his tutelage.
I have been at it for 9 months and just yesterday finished plug welding drilled spot weld holes to reattach both 1/4's. I average 1 day per week 8 hours working on it. I have MANY more days to go ...more welding at dutchman, and probably a week of nothing but grinding those welds flush THEN getting into the body finish process.
What consumed lots of time was taking two cars apart so I could get one back together and I was lucky to find a donor with parts.
To me, if I had the $$$ 7000 would have been a frickin steal!!!
see my pain at
http://s284.photobucket.com/albums/ll40/DariusCRCKBR/Bodywork%20Pics/