Some years ago, I was thinking about a used Airstream travel trailer. I had always heard they were the best. My research revealed that the longer trailers, about 30' I think, had frame problems in the rear. The rear actually sagged on some of them, on the super expensive Airstream! So, I would agree with Flying Fool about considering frame strength. Travel trailers are typically engineered to be as light as possible so probably not much margin on the frame strength.