If you're picking between the first or last day to use your ticket, I would probably use it on the last day. If you're taking Magical Express, you probably won't make it to Pop Century until some time between 4 and 5, then you'd need to drop your things at your room, and then make your way to a park. From landing to getting into a park, it generally takes us around 1.5 to 2 hours - and we travel carry on only and arrive early so we're just dropping bags at bell services right outside of transportation. On the last day, Magical Express will pick you up around 4:15 for a 7:15 flight, which would give you until at least 3ish in a park that morning. That gives you around 6 to 7 hours of park time (depending on how early they open that day), vs. 4 to 5 hours the first night.