Spot-weld cutter would be useful. There are over 20 spot welds that hold the angle strip to the side wall. Have you removed the paint from the strip? After doing that, you should be able to see the spot welds.
Do you intend to remove the plywood floor in one piece (and replace it as one new piece)?
I have not removed that strip or the floor, but I talked with a person who had done it. I cannot remember if, after the metal side strip was removed, the wood could be angled out the rear door, or if the wood had to be removed from below (with the body off the frame).
