I made the Yellow-letter sidewall Traxxas wheels into Whitewalls, still on Tamiya rally tires. Since i think the original 1960s look fit the truck a lot better: Gangster Whites with Poverty Caps
Also i've been watching videos of a guy customizing pressed steel toys, who is really into making them Patina Rigs, that mertioned great results with wiping on a paint additive "Flood Penetrol". Call it whatever Shine-juice, Patina-sauce, it adds some shine and protection to keep it from getting worse. It's based on Boiled Linseed Oil, but it wets and flows out better, and seems to dry quicker.
I normally consider "Patina" to be a swear word, but i'm still ok with it on this truck. I did dig into the repaint side of the bed with some scotchbrite, and knock the high spots off the rust.
Right now 2 coats of Penetrol even have the rust shiny and reflecting light. It didn't even screw up my Sharpie lettering from 2016.