a compressor driven dehumidifier is my choice. It will add some heat to the trailer, they draw about 300W so it's like a 300W heater. But can easily pull 5 gallons or more of water out of the air each day. If you want most have a external drain tube hookup so you can have it drain outside or to a drain rather than having to empty it.
Damp rid won't pull enough out of the air each day. Nor will a peltier device. the difference is cups or pints of water/day vs gallons or 10's of gallons/day compared to a compressor driven dehumidifier.
The drawback is they do emit "white noise" but most have a low setting.
