Question: I've always wondered if Booth shot those hunters because he was pissed off at that one guy for shooting the duck; or because he felt it was the perfect time to test the effectiveness of his home made gun. Any thoughts on this?
Answer: The two hunters had now seen his face so they had to be killed. If they reported Booth to the police as "a weirdo in the woods with a powerful gun" (or whatever) his face would become known to the authorities and his chances of getting anywhere near the president would be zero.
Question: After they search Leary's hotel room, they find a piece of paper that says "SW SKELLUM LA." We learn that the SW stands for Southwest (a bank he was using) and SKELLUM is a phone number. What does the LA mean?
Answer: LA is short for Los Angeles, which refers to the city Leary attempts to assassinate the president in.