I've never seen a question answered in the same minute - but I think, you're right on the money:good Angel Robinson Garcia would be another strong candidate, but he fought in "only" 19 different countries - as opposed to 24 for Perkins. I would be surprised if anyone can top that.
I think we ought to consider Archie Moore - he was a world traveler for matches throughout most of his 4 decade spanning career!
That, I think, would make him a strong candidate for 3rd place in this category, together with Mamby. There may be others up there, but not too many, I suspect.