We live east of Seattle with a moderate winter climate (typical overnight lows above 20 degrees), but I do the following when going south for the winter (maybe more than I really need to do):
Set furnace to 50 degrees.
Turn off water to house.
Drain water lines, but not water heater. (Of course, an argument could be made for draining the water heater, but it takes a long time and I am always in a hurry to get on the road.)
Empty water from toilet tanks.
Put RV anti-freeze in toilet bowls and p-traps.
Next door neighbor does a walk-around and walk-through every 2 weeks.