Hi Alicia! You and your children will love Pop Century! The theming is fantastic! I've never had problems at all with the buses to or from the resort. There is one bus stop, located in front of the Classic Hall. I've never found the walk too far to the bus stop, but if you think it's going to be an issue, you might want to look into a preferred room, which would be located closer.
Wishing you a magical vacation Alicia!