The Turtle was on a journey. This is like what people living on the Great Plains did.
The environment in the Turtle and the Dust bowl was both arduous and painful. The highway was edged with a mat of tangled, broken dry grass. There were thistles and thorns on the way. The Turtle had his feet hurt and the grass made him hard to move forward. These uprooted grass were caused by the dust storm. In the reality, the Great Plain was suffering from the Dust Bowl, so the grass was also uprooted. And also because of the wind, all plants were a mess. People on the way west could not find proper roads to walk on. The Dust and wind also made them difficult to move. The sun warms the grass. The embankment is steep. The Dust Bowl lasted for over 10 years. So probably many migrants were suffering from the hot weather, like the Turtle walked in the sun. There are many mountains on the way to California, such as the Rocky Mountain. The embankment was like all mountains, steeper and steeper.
In the passage, there was neither food nor water mentioned and we all can imagine that the Turtle was hungry and thirsty. He tottered in a slow and weary way. That is also similar to people’s experience. The Great Plain, which was used to be arable, became a desert. Therefore, we can imagine that people started their removal with really few food and water. Also, the Turtle had only his shell with him, which is rough and uncomfortable. This is also similar to the situation for Okies. Since they were poor, they could not bring baggage they need with them. They also had to live in Hoover villas.
There was tough, and some kind of malevolent competition among