I have made a connection to where you are. I have it on pretty good authority, (my wife has lived near where you are), that the problem you have is on that is real similar to the one occurring in the meth capitol of the US which is just down the road from you about 3 hours. The locals really do not want to hurt you and would be really frightened by someone who, has a gun, who is a crazy city person who would shoot them for just being on your property. (legal or not) or you are somehow connected to the DEA, FBI, CIA, KGB or whatever 3 letter organisation you want to use. All of them are connected in some way so getting the word out that you are going to shoot the next person who comes on your property would be fairly effective. something else to keep in mind if there is nothing to steal they will leave you alone. Make all of the things you value not visible, if you look like you have something they will steal it and make sure your opinions of drug use is well known. We have had people who really worked pretty hard to "be friends" and came to our house just to have a look at our cabinets to see if we had any drugs they could steal. After finding out we dont bother with that stuff they really did not want to "be friends' so much any more. The meth addiction or other things they are on will make them brave to get the next dollar for the next high. Something else would be to make sure they think you have an arsenal of selected weapons that would kill with extreme prejudice any who would venture close to your well designed abode. All of this would not have to be true but they need to think that it is.
Unfortunately this will remain a problem that will never go away. My wife lived there more than 10 years ago and the problems in the rural areas have gotten worse as the time passes especially in the poorer counties in the midwest. You are an easy target since they view you as a "city slicker" so you will need to change the perception to crazy gun toten willing to shoot first and ask questions later person who would shoot them and have what is left prosecuted and turned over to the DEA. drawn, hung, quartered and sent to the four corners of the empire. If you need any help in the drawn and quartered department the wife and i may have a free weekend coming up.