Learn about modify and refresh. Once you make a booking you can modify it. It will show you available rides you can just keep refreshing until you get a earlier arrive time or one for a better ride. I've seen rides showing no availability left for the day in the early afternoon and managed to get one with a return time 30mins away .last year I arrived in the Disneyland about 2pm and managed to get passes for all but one ride which kept breaking down that day