The kind counselor
Instead of turning this novel into a CPS horror story, we meet Miss Jean Bauer, an intelligent, resourceful social worker. Instead of permanently removing the parent and child, Miss Bauer decides to keep them together, but instead of living in the wilderness, the kind counselor offers them a chance to live in a house. Because she "made a home" for the two wanderers, Miss Bauer is functioning as a kind of savior character, showing that Caroline's father is solely responsible for their inevitable downfall, because of his extreme paranoia. In this case, the government treated them with the utmost respect and grace.
The paranoid father
Perhaps the father in this novel was the victim of military combat and PTSD, or maybe he is mentally disturbed, but in either case, he abducts a little girl and raises her in the woods. That, combined with his already paranoid personality, create an unstable life for Caroline. Caroline's only demonstration of proper human behavior is this man who can't stop looking over his shoulder. For Caroline's character development, this father represents her own inherited struggle with severe agoraphobia and paranoia.
The allegory of the young woman
This novel is at least in part a Bildungsroman, a quest toward maturity. The inciting incident is that Caroline is thrust from her wilderness paradise into the real world of society and government and commerce. When she ends up separated from her "father," she is challenged to solve her own problems and to make plans for her life, without her guardian to help lead her. This represents her blossoming independence.
When she chooses to get a degree and a job, that is an indication that she has what it takes to make it in life, but when she starts wanting to kidnap young girls, we see that there is still potential for Caroline's life to spiral into darkness. The journey toward her adult identity is complete at the point when she begins wanting to raise her own kidnapped daughter.
The other family
Part of Caroline's journey toward maturity involves revisiting memories she repressed. She returns to Idaho, frostbitten, alone, and in desperate need, but instead of rushing to a shelter, she finds her long lost sister, and she watches her from afar. She decides that there is not enough connection for her to return to the family who raised her, so she moves along.
This other family represents the normal life that Caroline could have had. In a darker sense, the fact that Caroline doesn't associate with the family shows her Stockholm Syndrome, in that she feels most deeply connected with a man who literally kidnapped her.
The allegory of evil
This novel does something very clever: it describes the process leading up to a horrible act of evil (kidnapping). Because Caroline never hated her father, she never realized that what he did to her was wrong. It was wrong of him to take a child into the wilderness. But then again, he educated her very well, he provided for her, and he raised her with an optimistic, hopeful outlook on life. However, he wasn't mentally healthy, and she is certainly not well adjusted.
This becomes a serious problem when Caroline begins feeling tempted to re-enact her traumatic abduction by kidnapping a little girl of her own. What she really wants is to have a baby, but she is interpreting that through her broken family experience. The effect is that without ever doing anything wrong, Caroline has discovered a temptation to do great evil.
