We stripped our 25' 69 tradewind's clearcoat and had good luck with Citrastrip. It cut through everything very quickly and isn't too hard on lawns or the environment. They make it in a gel that you brush on, and a spray can. We preferred the spray can, even though it was a little more per oz, it had less waste.
One thing to be very careful is that when stripping the trailer make sure you remove plastic items like your clearance light lenses because the stripper will ruin that. If the paint is already peeling chances are they didn't do the prep work right and that is good for you! Apply the stripper, let it bubble the paint, and if you have access to a good power washer use that to remove the paint, you don't want to use anything abbrasive. Once the paint is off, provided they didn't sand the heck out of it before painting, then you can polish the trailer if you want or let it go gray naturally. There are numerous threads about polishing, and you can read some at www.vintagetrailersupply.com
about their polishing system, which is the one we used.