You can purchase a Park Hopper Ticket which allows you to visit multiple parks in one day which might come in handy if you missed something and want to go back.
Normal Schedule – For most days, Magic Kingdom Park opens at 9:00 am and often closes between 7:00 pm and 9:00 pm depending on the season.
Magic Kingdom Lands include: – Adventureland – Fantasyland – Frontierland – Liberty Square – Main Street, U.S.A. – Tomorrowland
In a nutshell, Disney Genie is a free service that helps you plan out your day.