How would you handle this surface rust?

I did a quick search on the forum to see if this has been addressed and didn't find much. 2007 Tundra crewmax limited. The bed caps have rubbed and worn off the original paint, and surface rust has started to appear. Please see the attached pic. It's pretty much like this all around the edges of the bed. I'd rather nip this in the bud before it gets worse. How would you guys tackle this without doing a full bed paint job? Thanks for any advice!

 

if it was me, I’d use some rust converter liquid then use colour matched touch up paint. Looks like you don’t really see it when caps are down

 

I think I'd use making tape along the lower edge of the rust, lightly sand the rust with the creased edge of some 220 grit sand paper then paint with an artists brush using POR 15. The POR 15 is black but it'll be mostly covered by the plastic and not seen

 

I used Corroseal on mine & it has held up well. I also used it on my rusty trailer hitch. It will turn black when dry & you can use touch up paint/acrylic or just leave it. Mine has held up well & not grown any bigger.

 

Following. Got the same thing not really on the corners but across the entire top of the tailgate where the cap ends. Someone had a camper on the truck before I bought it and let the paint rub off. Been trying to find a bed cap the comes down farther than the stock one but no luck. Don’t really like the painted look but need to fix it soon.