What is the importance of San Francisco as a setting in the novel, All the Winters After?

Though only the final scenes take place in San Francisco, the city plays a symbolic purpose in the novel. After seeing a picture of the Golden Gate Bridge in a book on the Winkels' bookshelf, it became the focus of Nadia's intense desire to leave Alaska and branch out into the wider world. Gradually, as she gets to know Kache and he shows her things on the internet, her focus is narrowed to film school, and then the Academy of Art in San Francisco. At the end of the book, Nadia is on the Golden Gate Bridge with her scarf flapping in the wind like wings, a symbol of the freedom she has finally achieved.