Park-hopping at Walt Disney World's four parks resumed in February, and boy, are they hopping. Tickets to all four theme parks are sold out the week of Spring Break and some of the parks are fully-booked through mid-April, according to Disney's reservation system. Those who haven't already purchased tickets but were hoping to hit the Magic Kingdom will have to wait for slightly warmer days. The self-proclaimed Most Magical Place on Earth is booked now through April 9. Beginning this Saturday, sister parks EPCOT, Hollywood Studios, and Animal Kingdom are completely full through Friday, March 19. It's smooth sailing for guests starting April 11 when all parks show tickets available through the rest of the summer, but here are 5 things you should know before heading off to the land of Mickey Mouse.