Nikki - My Dad heads to Florida (usually November thru mid-April and has been doing it for about 30 years. Here are some things I know he does.
Disconnect car battery (he leaves it in the car in the garage) and jumps it with his other car that he drove to FL when he gets home.
Lowers his thermostat to around 62*
Shuts off all water at sinks, toilets, etc, but leaves all cabinet doors open so heat can get to the pipes and the pipes don't freeze. Also puts plastic wrap over the toilets so the water doesn't evaporate (dunno why he does that one tho). He can't shut it off at the main because he has base board heat.
Leave a lamp on a a timer. Luckily my cousin lives 4 doors away and if he sees the light doesn't go on , he goes and checks out the house.
He used to have the phone shut off, but now only lives with a cell phone.
Forwards his mail.
Also has a VFW friend drive past the house if he's in the neighborhood.
Big thing tho is make a list. Even after 30+ years, every year he forgets something (personal phone book, this year it was his tax papers), that I have to go get & send to him.
I'd also suggest you make sure someone trustworthy has a key. Just in case.
If I think of anything else he does, I'll let you know.