Update: I've sliced and diced all the rusted sections out of the floor and will be fabricating patch panels from galvanized steel, which are to be welded in. After a few coats of Tremclad and asphalt undercoating, it shall be all set! Pics of prepped areas below:
Pics of the removed driver's side floor pan below:
Looks like swiss cheese! More to follow.
Cheers, TheCanadian