Sorry to hear about your house, that sucks :-(
When I leave for a few days or more in the winter, I shut off my main water valve to my house, turn off the water heater and open up my lowest faucet to allow the water in the pipes to drain. Then if my heat goes off due to power outages, I dont have to worry about frozen/ damaged pipes. As others said, Antifreeze in the toilets is a good idea, if you dont drain those too.