Why do Taylor, Esperanza, and Esteban enjoy the day in the Cherokee Nation?

Chapter Fifteen: Lake o' the Cherokees:

Over the next several hours, Esperanza and Estevan seem changed. As they reach closer to the heart of the Cherokees, they see fewer and fewer white people. Esperanza and Estevan seem relieved to be around people who look more like they do, while Taylor is the odd woman out. They reach Lake Oologah, the Lake o' the Cherokees, one of the few diamonds of the Cherokee Nation. All of a sudden, Turtle cries out "Mama," but Taylor only sees a gas station and a cemetery. Meanwhile, Turtle and Esperanza become inseparable.

The four travelers find a cottage. Although Esperanza and Estevan object, Taylor considers this vacation a present, "as an ambassador of my country." Esperanza begins to thaw and in some respects return to life, seeming honestly happy when she holds Turtle. Although they insist that Taylor call them Steven and Hope, Taylor cannot get used to changing their names, and suggests that they only use the names when they need to fool someone. While Turtle and Esperanza remain on the shore, since neither know how to swim, Taylor and Estevan take a boat out on the lake. Estevan takes off his shirt to sun himself, and Taylor wishes to know how his chest would feel against her face, so she looks away. She tells him that she will miss them a great deal.

Esperanza begins to use English more and more often, and she discusses with them whether she likes sunset or sunrise better. Turtle attempts to bury a doll in the dirt, but Taylor explains to her that beans grow into bushes or trees when you plant them, but doll babies don't. Turtle says "Yes, Mama." Taylor asks if she saw her mama get buried like that, and Turtle says "yes." Taylor explains that it is sad when people die, because you don't get to see them again." That night, Taylor asks Estevan and Esperanza to do a great favor for her, and they agree.