In addition to the usual things like turning the water off to the ice maker, washing machine,and all sinks/toilets and putting the water heater on "vacation", we set the heat to 50 degrees. We have baseboard hot water heat and were told that the water to the house should not be turned off. We put bowl cleaner in the toilets and cover the opening with plastic film. We do not flush the toilet after the water is turned off. Doing that caused the seals to dry out and required repairs when we got back.
We got a seasonal insurance policy which was significantly more expensive than a regular policy.
We also installed a GE wireless security system with very easy to install wireless sensors. If you have Internet while you are gone you can get a wireless camera you can access via your page on the security company's web site. The security company we use is
FrontPoint SecurityIf there is a power outage there is a 24 hour backup battery and an email is sent telling you when it went out and one when it came back on. If it is out for more than a specified time you will get a call.
The system uses the Verizon data network to communicate with the monitoring company. It uses other providers like Sprint if there is no Verizon coverage.
We have door/window sensors, motion detector, freeze detectors, and flood detectors. In exchange for a big discount on the sensors you have a 3 year contract for $35 to $50 per month - depending on the plan.