I also see a very strong Huck Finn connection here. Huck was a poor white child with an abusive father and no mother who helps his black friend run away from slavery. Lily also has a similar family situation, and she helps Rosaleen run away from a racist, unjust legal system. Both Lily and Huck are about fourteen years old, and theirs is a story of personal growth. Throughout their journey, Huck finds his family with Jim, his black friend. Lily, likewise, finds her family with Rosaleen and the Boatwrights. In both Lily and Huck’s situation, they are raised in a society that belittles and mistreats black people, and they have been taught to be prejudiced. In Adventures of Huckleberry Finn, Huck has a defining moment when he has a chance to turn his friend Jim over to the authorities, but cannot bring himself to do it. Even though he “knows” that helping a black man is “bad” (based on what society has taught him), he says to himself, “Alright then, I’ll go to hell,” thinking that he is condemning his soul to hell for helping his friend. Lily has a similar powerful moment when she reveals the truth to August. She describes how she helped Rosaleen escape from jail, because she was afraid they would kill her in there because they were racist. She tells August, “I don’t mean to be a bad person… I just can’t seem to help it” (241). Part of the reason Lily thinks she is bad is because she sprang Rosaleen from jail, which is illegal, even though the jailers were mistreating Rosaleen. Huck and Lily both felt like they were being bad people for sticking up for their black friends, but in the end they realize the importance of these people in their lives and learn to look beyond skin color.
If it does, you may relate the situation with "To Kill a Mockingbird" due to the racial tension Atticus and his family face when he decided to represent an African American in the 1930's - same as Lily and TRay face when she decides to free Rosaleen and flee to August's house.
Another book that may be related - even August mentions it - is "Jane Eyre" because they both deal with the death of the main character's mother and the suffering it brings to this character.