[SkidmoreGarage]

Just had a realization, I think you are referring to the rear cab support as the b-brace. If your inner rocker is in good shape, that will be blocked off (hopefully). On the rear cab support, the front set of holes is bolted but the rear is spot welded in multiple place, so you can't even pry it really. You can only see into your front due to the rust hole through the inner rocker.

Also, it's easy to get frustrated that your truck isn't what you expected in the rust department. Keep up the good work. These trucks all rust. They were never designed not to. I have convinced myself that non-rusted trucks exist in 2 categories ones that were stored indoors and never driven (luck+$$$) or the ones that have never been thoroughly inspected and get passed on as "no rust survivors" to people who don't know any better... Like me