How do I prep areas like this?

[DanMcG]

I initially started out just wanting to do some patch panels to stop the rust, just to help preserve my truck which doesn't get used often, not do a complete resto on it. That all seems to have changed after hanging out in here. lol Now that I have most of the bed down to metal with 80 grit, and almost ready for epoxy, what do I do with the places that are near impossible to get to, or have to much shape to really sand it down, like around the stake pocket area and leading edge of the truck bed?
Other then sand blasting, which I'm not really set up to do, can I get away with a good cleaning then scuff with 180 or maroon scotch-brite?

 

[chevman]

80 grit DA scratch is for maximum adhesion, but those areas don't necessarily need it. So if you can't blast it then I would just clean it up as good as possible, the better the scratch the better the adhesion. Looks like it has held very well without good protection for decades.