Post up some pics when you get the front A pillar off, then we can talk about what to do as far as the floor. There is usually significant rotting behind that front pillar that is the deciding point for replacing the floor piece. one piece at a time
I question the rear pillar because it is hard to tell from pics if it is just flaky rust/pitting or structural on the rear. mine looked like light pitting but i decided to remove it anyway in doing the whole floor edge. When I removed it yanking on a partially connected spot weld the section I was removing cracked it in half. it was severly rotted on the back side. see pic (front of driver side pillar)
This may have just been a result of my super human strength
I will check in on you later this eve.