I tried to think of something other than apple-picking, but I’m 99% sure Coraline’s fall tradition is apple-picking with the other kids she grew up with. It started when they were little and their mentor Eliot was still around. Usually Gabel and Coraline were the only two actually picking apples because the other four were getting into some sort of trouble and Eliot had to keep them from hurting themselves. Or each other. After several years the four just stopped coming altogether.