Noob here. I recently purchased a 2011 Utility VS1RA 28 ft Refrigerated Trailer for a special project. The trailer will be hauled to a location and never moved again. I understand the roofs of dry van trailers are very thin and not meant to support anything. But how durable is the roof construction for typical reefer trailers? Can you walk on top of them? Could you mount solar panels on top without structural risk? Any information is appreciated, thanks!