None of my business, but if it were me, I would strip that Surly Pugsley down to bare metal. Even consider having it sand blasted especially around the joints and braze-ons. I would get out every hint of rust or corrosion, which is like cancer to metal.

Even better, maybe a custom bike builder like Black Sheep Bicycles in Ft. Collins, Colorado could build a titanium version of your Pugsley. To me, the best way to stop corrosion is to prevent it from starting in the first place, and that would mean TITANIUM.