Jeff, go to the thread shown above by PITOU49. Everything you ever wanted to know about your problem is there. I've repaired some stuff almost as bad as yours and posted those results. Scan back the last year at least and you will find most of what you need to get started. Filiform corrosion, KSC Corrosion Technology Laboratory -- Filiform Corrosion
,is easy to stop and keep stopped if you maintain. Our problem with the Airstream is, if we remove it, the skin color under the Alcoa applied clear coat is a different color and in some ways, looks almost as bad as the corrosion. I've found a pretty good solution, not perfect, but looks as nice as you can probably get. It's work, but to me it was worth it. info posted in the above Forum thread "corrosion problems with new Airstreams". Good luck.