Auto body questions

Well I got my scamp the other day and the body is a bit rough. The paint is chipping really bad. I wanna do something the body since this car will most likely sit out side for awhile. I dont want more rust than I have. I thought about sanding it all down and maybe a primer. But I was told that was a bad Idea. Because primer obsorbes mositure. Is there a sealer or someting I can used to protect it? So my question is what should I do. I want to protect what good metal I have. But at the same time Im not ready for a full on body and paint project. I put in a few photos so you can get an idea what im talking about