Please help me identify a cure! (Bodywork Newbie here)

Rust-Mort or Ospho. Ospho can usually be had at a local Ace or True value for about $12./qt. Very similar products but I like the Ospho a little better. It looks pretty rough from here though. The cowl has perforations so it really needs some metal replacement and where the quarter laps the trunk trough there's no good way to get in there short of peeling it apart. I think the rust products help but they are not a cure all. Hate to see you do a bunch of work and 6 moths later it's bubbling back up again.