Like jjustice I opted to have my Argosy painted in a truck body shop. The full process in pictures can be seen at post # 466 on my main thread here:
Four years later, and recently returned from 173 days out on the road, the trailer is show-room perfect, maybe cooler looking than when it came out of the Airstream factory.
I had the old paint stripped with aircraft stripper and acid washed before taking it to Wiltsie Truck Body for painting. They acid washed it again.
Some people on this forum warn about using the acid wash. I didn't pay attention to the detractors; Wiltsie is a 55 year old company that has been painting aluminum for all of that time. They know things too.
Doing it yourself is a lot of work. I know from the prep work we did ourselves.
If you do it that way the best thing you can do is to follow the tips from boatdoc in #2 above. I know that those techniques and products will work perfectly because I've used similar to paint the interior, as well as household furniture.
In painting, good preparation is everything.