Closing up for long trips:
Water: Shut off at main. Turn off H2O Htr (Don't need to drain). Unplug water conditioner.
Electricity: Unplug anything with a transformer.
Mail: Easiest is to have a neighbor throw everything in a box. And scan and email selected items (don't get much mail anymore).
Security: Have a light or two on timer. Pull drapes/blinds. Use security system. (Can you send me the provider for the cellular based system?)
Garage: Use/give away/recycle combustibles. Gas, oil, paint etc.
Yard: Buy a townhome or condo or plant easy care things like perennials. Reduce amount of grass by using perennials or decorative rock in areas.
TV: Cut the cable and get a digital antenna.
Food: Take ALL food with you and empty/clean and unplug fridge and leave open.