I'm really learning a lot from this post, thank you for the thorough writeup and pictures! My 1965 C560 school bus front clip is increasingly resembling yours.. pretty rotten. Because it's a bus, the factory front clip ends at the dashboard, but I can see its mount points to the frame are pretty bad. The Carpenter coach portion is remarkably rust free, so I think it's pretty much holding the front clip on. Also I'm sure that whatever Johnson era rustrpoof coatings they put on this thing are killing me slowly :-) but at least they'll find me in a rust free school bus.
I was today years old when I learned from this post about how to duplicate spot welds without a spot welder!
