Conversation so far:
Who did Cooper become friends with?
Cooper's twenty-year friendship with Ernest Hemingway began at Sun Valley in October 1940.
How did he become friends with Hemingway?
The two shared a passion for the outdoors.
Where did they meet?
Sun Valley.
What were some of Cooper's interests?
for years they hunted duck and pheasant, and skied together.
Did he have any other interests?
admired the work of Rudyard Kipling--Cooper kept a copy of the poem "If--" in his dressing room-.

Question: What else did he do in his free time?
Self-contained rewrite: Other than reading the works of Rudyard Kipling, what else did Gary Cooper do in his free time?