Hi Kathy! Welcome to planDisney!
I am so happy to hear that you will be visiting the Most Magical Place on Earth in just a few days! I hope you have planned some time at
Magic Kingdom Park to see Cinderella Castle all dressed up for the
Walt Disney World Resort 50th anniversary celebration. It is stunning!
I'm happy to tell you that you can add the Park Hopper Option to your
Walt Disney World theme park ticket when you are at the theme parks. I've done this a time or two myself! Stop by a theme park ticket booth or Guest Relations and let them know you would like to upgrade your ticket.
Keep in mind that you have to add the Park Hopper Option to your entire ticket. So, if your ticket is a 5-day ticket, you have to add it to all five days, even if you only want to park hop a day or two. Since you want to get the most out of your ticket, it's a good idea to do this on the first day of your visit!
I hope this helps, Kathy! Please let us know if you have any other questions.
Tabitha