ceiling rust

[cam.man67]

Above the windshield maybe an inch or so running the entire width of the cab, the ceiling is rusted through. As it the rust stops before the visors, it leads me to believe that it came from a poor drip rail. So my question is twofold:

1. How would I go about fixing the rust that's there currently? Would bondo be the best choice there, or are there ceiling panels I could weld in?

2. The drip rail I guess needs re-sealed. Will regular epoxy work for that, or do I need other stuff?

Thanks in advance.