Final answer:
Alfred went riding with Major, Hollis, and Sonny for an adventure or pursuit, with a specific goal in mind. The group may have been out to investigate or confront a situation.
Step-by-step explanation:
Alfred went riding with Major, Hollis, and Sonny because he wanted to join them in their adventure or pursuit. The specific reason for their ride is not mentioned in the provided references, but it seems that the characters had a specific goal in mind or were following a lead. The references mention that Alfred noticed someone riding hard and something being wrong, indicating that the group may have been out to investigate or confront a situation.