BoulderGal, what's probably going on in your case is that its also pretty cold, so that any humidity you have inside the warmer trailer is condensing on the inside of the windows and any other cold surfaces. Warm air can hold a lot more water vapor than cold air. As an example, air at 50 degrees and 100% relative humidity holds the same amount of water (same absolute humidity) as air at 75 degrees and about 40% relative humidity.  So its going to be hard to remove enough of that inside moisture to keep the condensation from forming, because whenever you breathe or cook something you're adding to it. 

Try the dehumidifier and see if that works for you. If the trailer is closed up during the day with no one inside it should keep up ok. When you're there in the evening the dehumidifier might not to be able to keep up so it might work better to open up a window a little on the leeward/downwind side of the trailer (keeping track of any wind direction changes) and also the fan lid and turn the heater up. The rising warm air will escape via the fan lid and draw in outside air from the window. That might sound counterproductive but the outside air has lower absolute humidity and as it heats up when it enters the trailer it will reduce the humidity in the trailer.

One other trick that you might try is to turn on the air conditioner and the heater simultaneously, leaving the windows and fan cover closed. The a/c acts basically as a big dehumidifier so it will pump out a lot of moisture. Lots of times on the east coast we run our a/c's just to dry out the air in our houses even when its not hot outside.  The pod heater puts out more heat than the a/c can remove so it will win the battle to control the temperature inside the trailer. This is for sure an inefficient (and noisy) solution but it should work and if you're not going to be paying more if you're using extra electricity then why not. 

Hope that all makes sense. Good luck. 

Thanks for the idea tho!

Susan

Let me google that for you:

Thanks in advance,

Susan