In case you haven't made the connection, what happens when water freezes in the lines and inside pumps, etc, is an expansion of the water. When this happens inside an enclosed object, it can split housings, rupture plastic or even metal lines, and rupture the water heater tank and fittings. Turn on the water pressure, and you've got a king sized mess.
Go outside and drain the hot water tank, it should have a small fitting on the tank itself. Pop the "Low point" drains on the water lines, and open ALL taps.
Open the outside drain for the fresh water tank, and drain completely.
Pour RV (Not any other kind) antifreeze into the traps, and into the bottom of the grey and black water tanks (a split drain valve is a real nightmare to replace). Most manufacturers will recommend refilling with 5 gallons of water, to keep the gaskets from drying out, but don't forget to top it off with half a gallon of pink stuff!
I also blow out the piping, but even go one further and disconnect the pump at both intake and outlet, and blow it out as well. If the pump is too hard to reach, then you could always pour a significant amount of pink stuff into the fresh water tank, and pump it until it runs pink. This charges all the lines (with your low point drains CLOSED of course) with pink stuff, and mainly protects the pump itself.
I also pour a small amount of pink stuff into the drain port of the water heater tank, since you can never drain it completely, anyway.
Pull the batteries and store them in an area that doesn't freeze, and keep a "smart" trickle charger on them.
This is the only time I actually shut off the fridge, and disconnect the power, since there is no longer a battery in the circuit.
I go through all this because I sometimes store my TT in Oregon, where the temps drop to 20 Below zero, for a week or more at a time.
We store on gravel, jacks up.
This year we are pulling to Texas, and will avoid all of that.
