I recently repaired/restored an entire floor section on a '64 122 wagon, 2 front & 2 rear panels, and both of the front "outriggers". These connect the sill (rockers) to the longitudinal box sections. I agree with the statement that this a major job, and certainly one worth doing correctly. In terms of time investment, it took me over a week of fabrication, fitting, cleaning and welding (a SOLID week; 8 to 10 hours a day, in a fully equipped shop!!). I'm still sort of a "newby", so I work slowly and deliberately. BTW, I'm a fan of a product I found at Home Depot. It's in the section for rain gutters, and is used to seal the joints. Dries a semi-rigid gray, and can be painted over. Cost about $5 a tube, and I used about 4 for the car, but I sealed everything in sight!

I think some pictures can be seen at my Flickr site
http://www.flickr.com/photos/10336839@N00/375184094/
Sort of new at this thing, too, so someone please let me know if the link doesn't work