Timbrass, that's some nice patching.
I love it when people come up with ideas like that. It's what drives the evaluation of the skoolie conversions forward.
To the OP
I would just use a rust converter on that beam, and paint it.
To remove and replace would be a massive, ugly, costly job.
"Don't argue with stupid people. They will just drag you down to their level, and beat you up with experience."
Patently waiting for the apocalypses to level the playing field in this physiological game of life commonly known as Civilization