I'm kind of looking at a 67 RS convertible. I noticed that the passenger door almost didn't have a gap and the front upper edge was pinched into the fender molding. underneath, the rocker seam was completely gone for about 2' and you could reach your fingers inside the back of the rocker. the outside was OK but I know its much thicker. It definately has a sag on the one side. I see there are replacement rockers for converties now. Would this solve the sagging problem? Is this a pro job or can it be done in the garage? does the rear quarter have to be messed with?
I appreciate your info and opinion.

New rockers would take care of the sag problem for sure. As far as doing it in the garage, it all depends on your talents. A dedicated fixture is a must to do it right. If one side is bad and your going to go to those lengths to replace 1, you might consider them both if your going to keep the car for awhile. To swap out the rockers, they are welded to the 1/4s, wheel houses, floors and toe boards and fire wall/cowl areas. Its a big chore and if the rest of this sheet metal is even marginal, consider replaceing it also.