2011 Tundra Bed Rust Advice

Any advice for this area of rust in the corner of the bed? It is flaking up pretty bad. Think I can get away with using a stripping wheel on the angle grinder? Or is it going to have to be cut out and patched? Also not sure if there is a bed mount under there that will complicate things.

 

I just removed my bed liner and have the exact same issue in the same spot. What did you do to fix this? I got a quote for $2000, but seams a bit excessive.

 

I didn't do anything. Truck has 218K miles on it, so I will take care of the mechanical and not be a perfectionist about the body. I found a deal on a camper top and bed rug, so now I don't look at it.

 

This is the nightmare I found after removing the plastic liner. The rust in the corners is the easiest to fix if you have to cut it out, because is flat and easy to replace. However, deep rust in the center section represents a problem because finding the corrugated steel sheet is next to each impossible.
I ended up buying some for GMC trucks and adapting it, then sanding and applying a thick coat of Herculiner.

 

I am glad I don't have anything quite that bad. I might cry. I think I'll go with the bed mat route and monitor for spread every once in a while. I will get it fixed when I have the cash.