Rust Repair Options

[geunther]

My truck was undercoated fairly early in its life. So there is remarkably little rust. The outter surface of the rocker is in excellent shape, as is the floor edge. They are both the original pieces as are the front and rear cab supports.

However: The floor edge/inner rocker has some rust through only where it is encompassed by the cab/floor supports.

My question is how to I repair the floor edge behind the side portion of the cab corner? Even with the rocker removed, I cannot easily get to where the hole is. I looked at cutting the end of the perfectly good rear cab support vs removing the perfectly good cab corner. I wanted to get thoughts on this. Thanks