If you are looking for metaphors and other examples of figurative language, a great place to start is the description provided of the changing seasons in America. The author uses a number of different types of figurative language to convey the beauty and the differences. Consider the description of fall at the beginning of Chapter 14:
After the keen still days of September, the October sun filled the world with mellow warmth. Before Kit's eyes a miracle took place, for which she was totally unprepared. She stood in the doorway of her uncle's house and held her breath with wonder. The maple tree in front of the doorstep burned like a gigantic red torch. The oaks along the roadway glowed yellow and bronze. The fields stretched like a carpet of jewels, emerald and topaz and garnet. Everywhere she walked the colour shouted and sang around her. The dried brown leaves crackled beneath her feet and gave off a delicious smoky fragrance.
Now, hopefully you will have noticed that in this quote there are a number of different examples of figurative language. Note how the description brings fall to life in all its beauty by appealing to as many of the senses as possible. We have the onomatopoeia of the leaves "crackling," enacting the sound, and we have the simile of "the fields stretched like a carpet of jewels," helping us to imagine the visual beauty of the fields in all of their bright colours. Remember, though, that a metaphor differs from a simile in that it asserts a comparison between two objects without using the word "like" or "as." Thus, the oaks that "glowed yellow and bronze" is an example of an implied metaphor, because the oaks are being compared to gold and bronze, precious metals, because of their beautiful colour.
Hopefully this will help you identify other metaphors in this great book. You might want to think about the description of winter that is provided later on in the novel and see if you can find any examples of metaphors there. Good luck!