You will need to use an electric space heater to keep the temperature well above freezing. In addition there are some other areas of concern such as the HW tank. In most RVs the tank receives little heat. If the temps start dropping into the 20s or below you might want to turn on the HW heat in the evening at least to warm up the water in the tank.
I would also recommend you get a remote temperature sensor so you can track the temperature from inside the house. I thought I had everything working but snow pushed down on the power cord to the point where the space heater stopped working. Fortunately I had winterized the water system and only lost some food items.
RV antifreeze is pretty cheap. You might want to winterize, not have to worry about freeze damage and save the cost of electricity for the space heater.
