Issues
The rust is a perennial issue on these; it's like the Roto-Rack Badge of Honor. You can decide if it's worth touching-up, or you can go wild and repaint the panel after sanding/rustproofing what's there. D&M's forte was neither thick porcelain nor rustproof materials, which makes it all the more fabulous when you find one that's in otherwise good shape.
When you say the hose to the upper rack is crumbling, can you post a pic? If I recall, it was a plastic tube that came from the bottom-left of the tank, then angled up and over to where the spray tube for the Roto-Rack was located. Show us what's there, and we can improvise a solution...