The tribe
Ernesto's starting environment symbolizes something deeply cherished by Mexicans about Mexican culture. In Mexico, the nearly universal individuality of American culture is really not seen in the same way. Every tribe has their pariahs, but for the most part, the portrait of Ernesto's life in Mexico is nearly-tribal. His duty is first to his community and then to himself, and his sense of identity is firmly rooted in who he is in his specific family context; indeed his family is his community.
The rurales
Another unfortunate aspect of Mexican culture is symbolized by the rurales. These folk are not locals; they are nationals or federales undercover. They are in town for reasons that have only been rumored. There are apparently violent resistances to the Mexican government nearby and these undercover feds are going to capture citizens and draft them into the army under threat of death. Ernesto flees with his entire community into the wilderness. The rurales are therefore the inciting incident of the plot for the symbolic effect that Mexico's history of government instability and tyranny is highlighted.
The motif of northward travel
North is the direction of stability and freedom in this novel. That is not really because of America either; it is geopolitical. Up in the American Wild West, the Mexicans are far enough from the government outposts throughout Mexico which formerly kept them in chronic danger. The reason that freedom feels northward is not because of some American Dream; it is because absolute hell and mayhem are unfolding in the south. The journey northward is defined through its own imagery. By the time they get to Sacramento, the seasons are much colder than before.
California as paradise frontier
California has archetypal value in North American literature which is defined by the documents written in the state's discovery. Those journals found in California something nearly heavenly, a sublime natural vibrancy that naturally attracted those in need of solace and refuge. Ernesto's family doesn't settle in the most beautiful parts of the country, instead pushing forward as if to remind the reader of California's quality as a frontier state. The paradisal imagery of California is further noticed because it is the promised land of this sojourner's "Exodus" from a corrupt and dangerous Mexico.
Money as a symbol
The symbolism that takes Ernesto and rakes him across the coals is money. Money is the bane of his existence from the moment he steps across the Mexican border. In the North, he is unable to make money in ways that people don't expect him to, which means that he is unable to demonstrate his academic prowess to employers. He just keeps getting stuck with jobs that feel below his station. Money is the giants who live in his promised land, and if he wants to attain happiness, he must figure out how he wants to earn money and find a way to succeed in that endeavor. That is what he concludes at the end of the novel.
