As promised, an update. I'm trying not to remove entire substructure panels, but rather splice in good for bad to hopefully preserve factory fitment since there will always be other pieces holding the alignment in check. The trunk floor will remain and the bad center section clearanced out for a custom rectangular cell mounted midway through the floor for added clearance, but will still fill with the factory filler.
Drivers Side behind the 1/4. No unpleasant surprises
Trunk extension survived, will need minor pin-hole repair.
Exposing the trunk rails to salvage them and the stamped VIN
Passenger side was a little worse. I have a new section of rocker to replace most of the missing area without removing the ENTIRE rocker.
Door hinge post. Going to splice in new (donor car) piece.
Front P/S frame rail. Needs more cut away. Have donor rail, just determining the size of the splice.