rjb, How is the rocker (back side) of the kick panel area look as well as the underside? Anything can be fixed if you have the time and paitence, seen alot worse.
Just from looking at the picture and not knowing what the back side/underside looks like I would...
Take a bunch of measurments, more pictures. Get a piece of flimsy cardboard such as file folders or poster board, make a template of what you need to replace. Go buy a sheet of 18 gauge cold rolled steal and have at it. Do not cut out the cancer metal until you are happy with your patch work. From looking at this, again only from the top side I would fab up one piece and be done with it, but it is really going ot depend on the back side because if you have no structrual metal left there then you will need to fix that area first. I call this the can of whoop ass theory
I take it by your attempting the floor pans you have a welder and know how to use it?
I have documented all my floor pan replacement, trunk pans, 1/4 patch etc on this forum and have plenty of pics if you need more help. Search for progress updates under my username and you will see some pics of what I did. Also there are some other guys on here that have done a very good job as well. Do some searching of the board and you will be amazed at what you find.
Bill