Seriously.....

It looks pretty solid above the rustout so take a grinder with some 80 grit and start about an inch up from the highest rust spot and stop when you find good metal that will be what needs patching. Then either get some sheet metal and make your own patch pannels, find another car and cut them out or find new ones and then spend twice the time doing the bodywork on the new ones just to make them fit right.
It's just metal!