Very cool trailer, what a fun project.
I have a 65 that was pretty heavily oxidized. I used a big jug of cheep polishing compound from a local auto parts store and Scotch-Bright pads.
The polishing compound was mostly a lubricant. I cut the Scotch-Bright pads into about 2" by 3" squares, enough for three fingers. I had a piece foam from an old closed-cell camping pad between the pad and my fingers (cut down abrasion on my fingers and spread the pressure out more evenly).
I kept a spray bottle of water handy and gave a squirt any time the surface started to dry out. KEEP the light to medium, don't push hard. Monitor your progress carefully, you only want to cut through oxidation not into the thin pure aluminum coating that is on the aluminum-alloy skin sheets.
Here are a couple photos of what mine looked like in progress.
I still need to use Nuvite Grade "C" and then "S" to get the final mirror finish. Or not. For now I have other things that are higher on the list.