Hey a567, welcome! All of that "inner perimeter body framework" was wood on those early cars, mostly reclaimed oak from pallets the parts shipped in on. For a street rod, most guys build a framework of 1" square tube that bolts to the frame and provides the needed support for the body panels. For a restoration you're looking at replacing the wood pieces that were form fit into the sheet metal panels.
I'm not sure about build threads that detail replacing wood with steel, and IMO the search function we have on the forum isn't the best. Others may disagree, but I find it to be pretty much useless.