December was Holling's worst month because he got his "guts burned" by his idol.(MickeyMantle) Mickey said that he doesn't sign baseballs for kids in yellow tights.
June was Holling's best month because while they're on the camping trip he sees the river a whole different way and decides not to tell anyone because it was so beautiful.
The war within himself changed him the most because he became more mature. An example of this is when he jumped in front of the bus to save his sister.
I would give Holling's Seventh grade year an A because he became more mature and learned to believe in himself. Like when he passed all the eighth graders in the cross country race.
The gutsiest thing Holling does in this novel is stand up to his father. This is the gutsiest thing because his father expects him to be an architect and Holling tells him he doesn't know what he's to an be but he will let him know.