[MetroMPG]

Thanks for those picture links of the rocker structure! We'll have more when I cut out my rust.

I suspect the hole on the "shelf" in the wheel well was caused by rust, and then salty water & dirt got inside from there. So if you could prevent the hole, you prevent the rocker rust.

I would still rust-proof the inside of the rocker. It's normal procedure (commercial aftermarket) here to drill access holes to spray rust inhibitor inside hard to access areas. Then you put greased plastic plugs in the holes.

I'm posting pics of the front fender rust in a minute. I'll add them to the previous post, above.