Class conflict is evident in the status of the work camps and the low pay the workers are paid. They live in relative squalor and there is often talk of revolt and rebellion.
Strength of family can be seen in the fact that the family stays together through most of the book no matter how tough times get. Toward the end, people branch off a bit, but they are loving and work together to keep everyone's spirits up and food, clothing, other basic needs taken care of for all members.
You can see the theme of hope in the last few pages where Rose of Sharon is selflessly feeding the old man with her own milk.