Holey mackerel

i have never done anything close to that sort of rust repair but my way of thinking would be to attack one portion at at time to keep the structure all together and not run into getting it all twisted up or mis -aligned. like a complete floor pan. then the trunk floor then moved to quarter panels and wheel houses. one thing at a time. forgive my ignorance if im off base here. you must know what your doing here to go this far down. id like to hear your plan of attack in detail.

forty years of mechanical and thirty years of building bodies and paint. but yes you should usually start from the back end and move forward. reason for this is everything in the back is welded. everthing forward of the quarters can be moved and adjusted because it is all bolt on except for your unibody structure. in which front, center or rear all need to be square,before any sheet metal can be welded and or bolted to it. i use datum guages to make sure there is no sag or sway and a tram guage to measure length and width and cross measure for squareness. the factory made alignment and jig holes just for this to purpose and reference. there are frame books and schematics for every vehicle ever made. so when everything measures to spec, your sheet metal should fit with minor adjusting. in out up down and so on. and of course the era of these cars were built on the premise of give or take an 1/8 of an inch. but if you stick to that thought. by the time you are done front to rear the car could be out by two or three inches. what i am saying is my measurement are on center. not give or take.