Ghost Prime, Only say is that it depends on many factors. Will the SHTF be an EMP? Yes you are right they will have a hard time going to the country. But if it is an economical collapse then it is a problem because it will not matter if the gas stations are open or not. The gangs will steal cars with gas and take the gas out of the tanks, they may steal gas trucks full of gas. They will find many ways to get to the country farms. They will come in like armies with 10 to 50 cars and trucks armed with weapons we have not seen.
You will have warning but can you stop these killers because they are killers today already so the are harden killers already.
Also one thing that many forget is that many of the federal prisons are not located in the cities and you know that when an SHTF those prisons are going to get over run and the guards are not going to wait around to see what happens. So you will get many hard core criminals going the the farm land because they do not want to go to the cities were they know there is no food and no water.
So I see no real safe place. Numbers is the name of this game. You need a good amount of good people to protect the area 24/7 when the SHTF.
Also which city are you talking about 50 gang members? If it is Chicago you are talking about thousands of gang members. So it depends what city is 100 miles from you and how big is that city and also is there a federal prison closer then 100 miles from you. Big questions? It all depends on what type of SHTF.