Hello, Nhi and welcome to planDisney!
With cooler nights and holiday decor, I love how December at the Walt Disney World Resort seems to sparkle with extra pixie dust. I hope you love every minute!
Now, let's talk about your plans to visit not only the theme parks, but
Disney Springs. With a valid theme park ticket AND a complimentary
Disney Park Pass reservation you are welcome to come and go from the park as you like including a lunch at Disney Springs. A standard ticket allows re-entry to one park for the entire day.
With the
park hopper option you will still need a reservation for the first park you'd like to visit of the day and then beginning at 2:00 PM you'll be able to visit whichever other park you'd like
(pending availability). So in the example you gave above if you decide to start your day at Disney's Hollywood Studios, you'll need a Disney Park Pass reservation for that park and then you could leave for lunch at Disney Springs and then visit EPCOT to close out the day.
Nhi, I hope this helps as you're looking ahead to December. Best wishes for a Magical trip. Please come on back to planDisney with any other questions.
Lauren