Here are my two centavos:
If you have access to 120VAC, a powered dehumidifier is best. I don't like having it drain to the gray tank because a freeze could cause the trap in the shower to crack. It may be a chore fetching the water every so often and dumping it, though.
If no access to power, I would buy a few
Damp Rid tubs and place them in five gallon buckets. I would have at least two of these. Alternatively, place the absorbers in the bathtub or sink. Because calcium chloride is caustic, I make sure to take precautions and have a secondary layer of "insulation" should the primary container rupture (like a freeze cracking it.) Damp-Rid containers do not work as well as a compressor based dehumidifier, but they do work.
Avoid the tiny, Peltier based dehumidifiers. Those are worthless, in my experience.
