Surviving a nuclear attack is doable, provided you are:
Outside the flash zone Outside the shockwave / concussion area Sheltered from fallout radiation Have access to a constant source of uncontaminated water Can survive the following saturation nuclear attacks (from SS18s etc) Able to survive the civil unrest Disease Dwindling food source
Have I missed anything?
It might be included in this, but you'd also want to have an air supply isolated from fallout.
Maybe.
During the cold war most people in the valley assumed they would die immediately if there was a nuclear war.
Certainly hitting Oshkosh Wisconsin or Lima Ohio would damage the countries military capabilities vastly worse than hitting SV today.
Surviving the aftermath would require blood, sweat and tears.
When civilization ends and humans are thrust back into subsistence living, we are essentially back to tribalistic animals having to endure rampant starvation and disease. Life is going to be hard for everyone, but especially those without tight groups/tribes and without arms.