What Kodiac said! You cant, and you need people.
I thought my garden and fruit trees were well hidden: in the middle of 6 acres of uncleared brush, trees, palmettos, etc. cannot be seen from anywhere. I cant see my neighbors, and they cant see me. Or so I thought, until I ran into my new neighbors that are renting the place next to mine. They were poaching deer in my wetland right behind my house, well onto my property. They said they saw the fence posts (no wire). They asked to put a deer stand up and pointed at a tree, and then told me it was just past my garden, and pointed to where my garden would be if you could see it. They had been tracking deer throughout my property for some time. I never even knew till I heard them right behind the house one day. They know everything I have outside and I don't trust them at all. They demonstrated no respect for private property even now during normal times. and from the shooting, are well armed.
My wife hired a lady down the street to clean our house once a week. She has been doing it for 8 years now. we know her and her family, like them, but still, they know all my stuff inside. Food preps, gear, even the books I have been reading. So I have talked to her about prepping. Don't know if she does, but she knows what I have, and if SHTF, I bet she would come knocking, and probably with others.
The USPS local delivery person must know what i have, based on catalogs, magazines, and such.
Too many people know too much!
So how to defend against them? numbers, more people, and a constant watch.