First thing I can think of is to make sure there is no water left in the pipes that could freeze, we do this by turning the pump off and then turn the tap to an open position and blow through the tap - we do this every time we use the Dandy just so there's no water left in the pipe or pump. If you have a Destiny with en-suite make sure you empty not only the cassette but also the flush ...... a friend of mine had his freeze over winter
Perhaps you use bowls of salt to absorb moisture or the type of things with granules that do the same thing.
We don't pack our Dandy away for winter but we do leave the cheap dehumidifier boxes that you get from large stores inside .... they smell nice as well as absorb moisture.