Everybody has their own way, but I've had success with my Porter Cable 9424 random orbital, and Rob Baker's notorious truck box polish, as discussed by Geven on Jordan's thread here:
Check out post #752 for some pics of Geven's trailer and some details on his methods, and check out post# 762 below for some pictures of the finished product on one of Jordan's trailers, it's pretty stunning.
All in all, this method works well for me, it's quick, and you actually stay pretty clean so it's easy to work in a little polishing time after work or early in the morning without having to take a shower immediately. In a few places I've had to use my Makita buffer/compounder, wool pads, and Nuvite F7 for heavier cutting, but overall the Porter Cable and Diamond Brite truck box polish are good, clean, and quick. I believe one key is the cotton bonnets, I bought a bunch from Geven and I'm not sure where he sourced them.
This is what I got with only 17 hours total spent on my own trailer (covering about 80% of the surface area, I didn't do the top streetside, or curbside above the awning rail). It was a nice shine at 10 feet, though there is still oxidation and pitting around the trailer.
I did take a couple detailed shots of the front lower panel that features the Airstream nameplates and badging. Here's the before:
I removed the badges and cleaned up the small, oval MHMA badge a little bit. Almost two years ago, I had purchased a replacement Airstream nameplate, and I finally had the opportunity to install it.
My results weren't quite as dramatic as Geven's and Jordan's, but I didn't spend much time at all on it. One Saturday, and then a handful of 1-hour slots here and there in the evenings.
As always, tthere are a lot of ways to do something. I chose a method that worked well for me.