Are the large dogs ill and or elderly? No reason for them to be in the camper that much. Large dog give off more heat than a human and more moisture too. Animals survived long time before Central heat, they'll be alright outside long as it's not chained to a tree 24x7. Need walks to lubricate joints and circulate blood to cold paws.
Put the dehumidifier in the shower or on top of the toilet or under the dinette. My trailer is smaller than yours, one side of the bed is the dehumidifier, the other side the oil filled heater.