turn off the main water valve, turn the heat control to vacation, and
put in a thermostatically controlled low temperature switch that will
flash a light if temperature gets too low.

do know that vacant homes tend to have bad things happen arson,
break ins etc. you might have a security system installed to protect
the home and contents like tools etc.

also be aware homeowners doesnt usually cover a long term vacant home,
but if you tell your insurer homeowners will sky rocket in price. dont
tell them and arson occurs they may not pay.

might be worth it to offer home to friends to live there real cheap
till your ready to sell. provides built in security and activity.