Anne Marie Wheeler explores bomb shelters from the 1961 Community Fallout Shelter Program. She visits caves that were used as shelters in sparsely populated, but militarily important, parts of Idaho:

In an area with very few large buildings capable of supporting a community shelter, and an economy that certainly wouldn’t support a new, large suburban shopping center, the cavernous landscape provided a natural, but very afterthoughtish answer to the shelter question. I haven’t found a whole lot of information about what made certain caves suitable shelters and others not, aside from the ability to create a "spot" within the cave turned shelter for less than $100 ($775 in 2012). A spot seems to have included 1 quart of water, 700 calories of food (that’s one Big Mac) per day, along with, sanitation supplies (toilet paper, cups, etc.) and radiation detection instruments for one person. No word on bunks, blankets or anything of that sort.