I'm attaching a bunch of photos. As expected, the bottom is completely rusted out. I'm wondering how to create new bottom rails to hold the cart together. I'm not a metal fabricator so it would have to be fairly straight forward. If there's a rack I can get from an old Silver or Gold, that would be fine. Clearly it needs something to maintain structural integrity at the bottom (as Bruce and others were discussing) once the panels are removed.
View attachment 43195
I had a similar issue when going through my rebuild. I bought angled steel and bolted it to the frame: