Homes set back in the woods may need an early warning system, a system that alerts you that someone is prowling your property or sneaking up on the home. If you are off grid using alternative power sources, you may not have enough electrical resources that would allow a wired alarm system and/or surveillance cameras, so what is the alternative.
You can make ad hoc systems, and they can be complicated ones that require some electrical skills, or simple ones that essentially use noisemakers to alert you. You can use battery operated wireless sensors, for example, that are activated once an invisible beam is broken. They can be placed virtually anywhere within range of the wireless alarm, which would be on your person or close by, so it can be heard.
Other methods would include trip wires that have noisemakers attached. You could repurpose wind chimes to use as noise makers, hollow bamboo tubes, tin cans or anything that could be attached to fishing line for example, that would make noise.
The trip wire itself would be at locations where you would suspect foot traffic and the noise maker would have to be close enough to your home so it could be heard. You cannot string the fishing line 100 yards out and have the noisemakers in the same area. You would have to string line back to the home in such a manner that when the remote line was tripped it would essentially yank the noisemakers close to the home into action. This will take considerable line and some planning but it really is a simple concept that works.
If your home is set off the highway then there is a road or path leading up to the home, which is easily recognizable. People with no ill intent would obviously walk or drive straight up to the home, using the well defined path, and of course some with ill intent might as well. However, most people up to no good would not want to expose themselves along an obvious path to the front door so they would go off road as it were. This is where you would want to consider placing your trip wires.
Place the wires along parallel paths to the home, so you are alerted when someone is trying to avoid the driveway or walking path. Obviously, you would have to place trip wires that would encircle the home, not just along any obvious paths or roads. You cannot cover all avenues of approach, but you can cover the most likely ones you would use if you wanted to sneak up to your home and then cover some paths not so likely.
Each location would have to be documented, so you and others in your group or family can avoid them. This means you would need a sketched diagram of your property and as trip wires or alarms are placed they would be noted on the diagram.
You will of course get false alarms, because animals will undoubtedly trip some of the alarms, as would hunters or hikers. Avoid placing the alarms along obvious game trails or hiking trails.
People trying to hide will move along hedgerows and tree lines for cover, so place some in these areas in high grasses that run along the hedgerow or tree line. Avoid trampling the grass as you string the line, because anything that looks out of place would make some people more alert, and thus may spot the wires.
Trip wires are by no means foolproof, and no system is if someone has the time to study the defensive measures. In today’s high tech world, people however, expect advanced technology, so they may not even be considering such a low tech alarm system, and so would not be looking closely for one.
Most people would look for cameras, heat sensors and motion activated lights. You can place dummy surveillance cameras that can be easily spotted around the area, so intruders would focus on the cameras, and take measures to avoid the cameras, and as they do they would be more or less funneled to an area of your choosing.
Place the camera and then imagine what you would do to avoid the camera’s lens. Once you have figured out the most logical way to move to hide from the lens, then you know where to place a trip wire.
You have to put yourself in the shoes of someone wanting to avoid detection as they move toward your home. You will have to look at all sides of the home, not just the obvious ways of getting into the backyard, front yard and so on.
Ask yourself, can someone swim or boat up close to the home if you live near a large body of water. Can someone paraglide in, can drones be used and so on. Some of this is extreme but when placing yourself in the mind of a criminal, professional soldier, law enforcement personnel, or others, you have to consider all angles, all avenues of approach.