We urbanites would die from lack of potable water. Sure, there may be streams and rivers nearby, but the water is polluted from pesticide and fertilizer run-off, vehicle leaks and spills, and other surface contaminants. Boiling water will kill bacteria, destroy parasites, and remove some impurities (ammonia, chlorine, and certain heavy metals), but many pollutants will remain. It’s possible to build an effective water purifier (http://www.hutchbook.com/Bottling%20Water%20&%20Filters/default.htm), but most of us wouldn’t have instructions (no more internet) or the necessary materials.
For anyone living with cold winters, the next problem is heat. Even if a building has oil heat, the furnace needs electricity to run; also, when the tank is empty, there won’t be any more heating oil deliveries. The only way to survive winter is with a wood-burning stove or plenty of fireplaces.
These obstacles are followed by the dangers from other human beings. Chaos and desperation don’t bring out the best in people. If you have a warm, safe home, someone will try to evict you and move in. If you have plenty of food, other people will fight to steal it. No more government means no police, no courts, and no jails or prisons; people are free to harm or kill for what they need, and many won’t hesitate to do so.