[njsteve]

The main thing is this: you have to stop the rust or else anything you do is just cosmetic and will come back to haunt you in months or years to come.

Think of Joan Rivers. Just because she gets a face lift every few months doesn't mean she's young again below the (ever tightening) skin.

You have to stop the rust and the only way to do that is to access it. So you have to cut the surface material away and kill the rust, then clean the area, and the flap and reattach it. Then you do the normal bodywork after the repair is done. It's not that mysterious.