Staying there you can take advantage of early entry it alternates which park depending on the day. For the CA adventure early entry day make sure you line up early if you want to get in the park quickly because it gets busy. There's a nice cafe there called whitewater cafe it's a great breakfast stop cheaper than the main restaurant they have snacks, you can even get burgers pizza etc too. There's also a few things you can do at the hotel
https://disneyland.disney.go.com/hotels/grand-californian-hotel/recreation/. You're definitely in for a "magical" experience great choice!!