Quit breathing! Sorry, that sounded harsh... but it's sorta true. Contrary to what people want to believe, these molded trailers (most) are not built for cold weather. Your Burro
sounds like there's only air between the hulls, no insulation and certainly not a vaccum.
Prior to the big hack of FiberglassRV, someone posted a thread that spoke to the amount of moisture that's put into the air by just breathing in-and-out. Something more than a QUART of water per person in an 8-hour sleep. That water
has to go some place. Those of us that have "rat fur" etc. know it doesn't just disappear. Curtains, carpet, cushions all aborb that moisture... it doesn't just drip on us in the morning.
Truly, the only solution is to keep the inside temperture the same as the outside temperture and hope keeping air moving inside assists.
There's a reason double-pane/storm windows
are popular/used in stick built homes....
Sleep warm, but the more even the temperature inside and out the less moisture.