Body doesn't look that bad to me....top looks fine from what I can see. I haven't seen the inside, but it looks like surface rust. A body guy should be able to quickly get the roof back in shape. Cab corners are an easy patch as well as the floors.
Once you are done with the body work (that you are going to do) then I would suggest can or gun spray paint and the best way I have found to make an older looking paint job is to have layers. Shoot some black on first to protect it, then some colored primer (color of your choice). You can then wet sand to get a semi gloss look, and have some of the black show thru. You can also use any base color you want as long as it is paint as opposed to primer so it protects against rust. Allow more of the under-color to show thru on top surfaces such as the top of hood, fenders and roof.
