It really depends on what altitude you will be parking the RV at, and what town it is. It might be reaching down into the teens at night, and any water left in the water lines inside the coach can freeze, expand to 25% larger size, and burst even copper pipes, these plastic ones will not stand a chance.
You can buy a low cost air fitting, and then run a generator and air compressor to blow out the water lines with air. Then no costly anti-freeze or bad taste left over. Or you can blow out the air lines at home, and not need to take a generator or compressor with you. DOn't count on being able to use a air compressor at a gas station to blow out the air lines, it will take over 5 minutes, and they are not that patient for you to set everything up and run the compressor that long.
At least drain the water heater, or if it stays full of water, then leave it on all night, so it will stay above freezing. One bad water tank is about $350 to replace it. There is a 2" diameter air hole going right through the center of the water heater, so it will reach the outside air temp very quickly, and if below 25 can freeze solid overnight, expanding the water by 20% or so, breaking the aluminum tank into peices.
Good luck,
Fred.
