What is a thesis about peace and conflict in A Separate Peace?

John Knowles's A Separate Peace explores several different types of conflict. The narrator, Gene, is telling the story of a year of his education at Devon School, a particularly eventful year in his personal life. The conflicts he experiences are both internal and external. He faces external conflicts between himself and other students, like Leper, Brinker, and even his best friend, Phineas (Finny). Gene also faces a serious internal conflict, which is the central focus of the novel, wherein he has to reconcile himself to his role in the accident that led Finny to seriously break his leg, ending his sports career. The novel also takes place in 1943, so the interpersonal and internal conflicts take place against the backdrop of World War II. More importantly, our characters are young men, some of whom are considering signing up for military service, while others worry about being drafted to the front. 
In deciding on a thesis for the way conflict and peace are presented in A Separate Peace, you would probably want to decide which conflict is most essential to the text as a whole. Because Gene is a first person narrator who offers us plenty of internal monologue, I would argue that despite the grand international conflict at the novel's margins, Gene's struggle to understand his feelings toward Finny, his role in Finny's accident, and, later, his attempts to reconcile what he believes he did forms the central conflict of the novel. In some ways, the novel is Gene's attempt to make peace with his guilt about Finny's injury. You might consider to what extent Gene is successful in finding this peace in the novel's closing pages.