Aloha, Caitlin!
Welcome to planDisney, and thanks for sharing your question so kindly. It's always a pleasure to help a friendly Guest like you!
I'm glad to share that you'll be able to make the upgrade when you get to the
Disneyland Resort as long as there's availability. Once you get there, go to the ticket booths and talk to a Cast Member about your upgrades. They will be able to check the calendar and make the upgrade if there's availability.
Getting
Park Hoppers at the Disneyland Resort is a great move because the parks are very close to each other. If you combine these tickets with
Genie+, you can unlock faster access to attractions on both theme parks and maximize your time even more!
I hope you have a fantastic time at the Disneyland Resort next year, Caitlin. Please let us know if you have more questions and we'll be glad to help!
May the magic be with you,
Julie