B. Highway 66 (Chapter 11-15)

The Joads' journey to California begins in Sallisaw, Oklahoma and leads them to Route 66.
On the way there, the Joads have to stop at a service station for water and gasoline. There, the Joads' poor dog dies. This is significant because the dog was part of the Joads' old life - the one they had to leave behind to start new lives in California. They most likely had the dog to help herd farm animals that of which they do not have anymore. Or they could have had the dog as a companion. But they are leaving everything behind, so the dog has to go too.
On the end of the first day of their trip, the Joads decide to stop to rest with another family, the Wilsons. Poor Granpa suffers a stroke and passes away. Granpa did not want to leave his old farm life. He didn't want to let go - he wanted to stay. Therefore, he had to pass away. To go to California meant to leave everything behind and to start new lives.
On this road, the Joads and other migrants have their perseverance tested. How far can they go without wanting to turn back to their old lives? Can they accept the losses they will go through?