What do you think of this?

Doesn't look too bad. If you want to try to save it, its possible. What is around the small holes? Is it lead? Or just the panel is a bit rusted through? If possible I would mig weld the holes closed, grind the panel good, and use a good fiber reinforced filler. Duraglass works great for that. Then do your normal filler work on top. I have never had an issue putting plastic filler over brazed welds.