Rust issues and PO half a** fixes

[JimmyFloyd]

ok, so I thought the PO fixed a lot of the issues with the truck, but I noticed recently as I am removing parts that he didn't do so good.

This is the lower portion of my firewall after I removed the inner fender



As you can see, some parts are "fixed" and some are not. And the welds are pretty rough. Rocker Boxes were removed because "they trap dirt and always rust, so I decided they weren't needed"

this is a little closer look near the center:



and here is the underside:





As you can see, there are some new parts, and some were put right over the rusted one (floor)


And now my question about fixing this. Can I just get a truck cab (I have one located) and use this corner and floor from it to replace mine?