Hey there, Rebekah! Welcome to planDisney!
A Disneyland Resort vacation during the most wonderful time of the year! Your trip sounds magical already! Cars Land is one of the most festive areas to enjoy during the holiday season, so I hope you'll check it out during your stay. Not only does Cars Land welcome the holiday season with some of the most fun decorates in all of the Disneyland Resort, but there are also multiple ride overlays that help usher in the season!
Mater's Jingle Jamboree and
Luigi's Joy to the Whirl are can't miss rides in December!
Rebekah, I'm glad to hear that you've already made your hotel reservations. The more you can do ahead of time, the more you'll avoid having a "Nightmare Before Christmas" on your hands!
Theme park tickets go on sale 120 days in advance, so a late December vacation is not quite ready for purchase. I recommend marking your calendar for 120 days from the last day of your vacation so you can purchase tickets for the duration of your trip.
If you'd really like to get the tickets purchased now, you can do so and make
theme park reservations for any of the days that are available when purchasing, even if they aren't the days you'll be visiting. Once your actual park days open up for reservations, you can simply cancel your "placeholder" reservations and make new ones for the actual days you intend to visit! This is a bit more complicated, so if you're on the ball, I'd recommend just visiting the Disneyland Resort Website at that 120-day mark to purchase your tickets.
I hope this helps answer your question today, Rebekah! Enjoy your vacation!
Ashley