Not really. There is no sliding anything in place with the aftermarket patch panels. What I do is see just how much of the replacement panel I need and how successful I am at getting all of the spotwelds, etc loose. If you really take your time it could be easy to just replace it, but somehow I always run into problems that require some cutting of the replacement panel.
Do one at a time, or go ahead and put an X in the doorway with some 1" tubing or something. It's not hard to tack it in. Be strategic how you do it so you can get in there to weld! I am not sure how others feel, but putting the floor panel in first is probably a better way to go. That way the under floor support is preserved. You never know what you are going to find behind things. I ended up on one project having to remove everything below the floor and reconstruct it all.
