The nuclear sites are right on the water. If every road was down there was still the sea and we are talking for the most part about very obtainable supplies..food, water, safety gear, cots, blankets. To say nothing of generators, hoses, etc. There was also the air. Helicopters etc. would be in short supply but this would be extremely high priority. And there are other countries who were trying to provide assistance. They could have walked troops or volunteers over some of the roads, torn up to be sure, but they looked walkable to me. THere are carts, animals, bicycles. Viet Cong could have figured it out. mg