Small towns are wonderful. But many people require specialized medical care for survival and quality of life. Eventaully you'll need a dentist, opthamologist, gastroenterologist, etc, with modern facilities. Not to mention medications.

Larger cities (50,000+) will likely have those resources, even during a financial collapse type scenario. Larger cities also tend to have robust trade/barter systems. Again, small towns are great, but our dependence on cities for acccess to goods and services is here to stay.