Why is Allendale, California the perfect place for "There Will Come Soft Rains"?
I'm not sold on the concept of Allendale, California being "perfect," but I do think it is a good choice for this story's setting. California is a leader in the technology industry. There's an entire region called Silicon Valley which is basically dedicated to propelling the tech industry forward. Silicon Valley is located in Northern California. Specifically, it is just south of San Francisco. Using a straight line, the distance to Allendale is only 50 miles away from San Francisco. That puts Allendale very close to a major technology hub. If any house is going to be fitted with all kinds of futuristic gadgetry, it's likely to be a home that is located near innovative technology hubs. Allendale fits into that category.
The proximity to San Francisco also leads to another reason why Allendale is a good choice for this story's setting. Being such an iconic city and having such a dense population, San Francisco is a believable target for a nuclear weapon. Allendale is far enough away from San Francisco that Allendale would not be leveled due to the blast. The house in the story is still standing, but the people are dead, and the dog dies from radiation poisoning. An average-sized nuclear bomb, detonated at ground level, would produce a fallout cloud that would easily reach Allendale due to the prevailing winds. I've attached a nuclear bomb simulator website. It allows users to select the size of a bomb, type of detonation, and location of detonation. Several of my bomb selections cover Allendale in radiation fallout.