tat-tude dually
+1y
Well you have a couple different ways you can go as far as I can see.....
1 - is as someone else stated you can reskin the the roof
2- It looks like you could sand most of that rust off that roof and be ok with it....and then weld in a new piece of metal in that hold and then bondo what needs to be filled.
3 - you could get some rust stopper. I use POR-15 for issues like this, and then you could bondo over it. Whats nice about POR-15 is that it kills the rust and hardeneds the metal. You can sand over it bondo over it and paint over it.... It really does wonders for rust!!! here is a link POR-15 link and all you do with this is paint it on with like a house brush. and its easy to sand etc....And again you need to weld in a new piece of metal where that hole is before doing anything else.
If you got any questions please feel free to ask....