Hello there, Christina! Welcome to planDisney and thanks for your question!
Hooray! A surprise
birthday trip to the Happiest Place on Earth sounds so amazing! Your son is going to have a blast! I have stayed at Disney's Paradise Pier Hotel a few times and have loved every visit. The rooms have bright and beachy decor and come equipped with a mini-fridge and a single cup Keurig coffee maker. There will even be a few varieties of coffee and tea provided to brew in your room.
As far as cakes go, you can pre-order a
celebration cake to enjoy after a lunch or dinner in the parks.
Make a dining reservation at Blue Bayou Restaurant, Cafe Orleans, Lamplight Lounge, River Belle Terrace, or Wine Country Trattoria. When completing your reservation online or on the Disneyland app, you will see the option of adding a Mickey celebration cake that will be delivered to your table. You'll be able to choose the flavor and the message you want on the cake. These cakes are adorable and absolutely delicious!
I would also suggest that you call Disney's Paradise Pier Hotel directly at (714) 999-0990 and let them know that you are celebrating a birthday! They can usually note this on the reservation so they will be ready with complimentary celebration pins at check-in that you and your son can wear at the parks. They might also have some unique ideas to make your stay at the hotel extra special.
I hope your son has a fabulous time celebrating his birthday at the Disneyland Resort!
-Linda