Aim the automatic sprinklers at the doors and windows, and connect them to motion detectors.
There was a time when all of my neighbors were elderly and would sit out on their front porches all day. They knew everything going on in that neighborhood and they'd watch my house like a hawk. I could never sneak anything or anyONE in or out of my house without them noticing! I'm serious! When I bought some new gadgets, my neighbor asked me a few days later, "I saw that large box you were moving into your house. Did you buy a new TV or something?" I used to refer to him as Old Man Nosey. He notices EVERYTHING! So..... when I'd be gone for a while, I had no worries, I knew they'd watch the place. I have new neighbors now. I haven't met them yet. If I were to go out of town, I'd probably have a friend watch the place.