Never, ever, ever put a cover over an Airstream. The aluminum will get permanent unsightly wear marks in it from the cover touching the skin.
Wash with mild soap, wax with a non-abrasive car wax. Have a look in the forums for many, many opinions on what to use. I don't have a dog in that fight. Ours in a 2007, and I wash it only when it gets really disgusting.
San Diego--my favorite city. Lived there 17 years and still visit from Corona, CA area (just a few miles south of Anaheim on the 15 freeway). Welcome to the forums.
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'The Silver HamShack' (2007 International 22FB CCD 75th Aniversary model)
Multiple Yaesu Radios inside and many antennae sprouting from roof, ProPride hitch
2012 shortbed crewcab 4x4 Toyota Taco TV with more antennae on it