Does damp rid have a place in rving in winter/cooler temps

Make sure you open a window when you turn on the vent fans.

When we camp, I always have the bathroom roof vent opened an inch or two and a window in the living area opened an inch to allow for ventilation.

Your propane wall heater will draw power, but it is just a fan -

Do you have a multiple battery solar system? If not, it may be something to look into so you have more stored power available.