Hello there Kelly, welcome to planDisney! How exciting that you'll be visiting the "Happiest Place on Earth" so soon!
You'll be able to add
Disney Genie+ Service as soon as you tap your tickets at the entry gates to the parks. You can open up your
Disneyland app to purchase the service, and begin making your
Lightning Lane selections right away. The "Tip Board" in the app is the best place to see the wait times for attractions, and when the next Lightning Lane selection is available to book for each attraction. It's where I start each time when I'm planning out our day.
That is a fantastic question about which park to start in! It truly depends on what your priorities are as a family. If you have
Star Wars fans, you may want to start in
Disneyland Park so you can head right to
Star Wars: Rise of the Resistance and explore
Star Wars: Galaxy's Edge. If Marvel Super Heroes are more your speed, then I highly recommend starting in
Disney California Adventure Park and heading straight for
Guardians of the Galaxy - Mission: BREAKOUT! to jump start your day. I'd take a look at the list of
attractions in both parks to give you a better idea of where you'll want to start your day, but you truly cannot go wrong.
I also wanted to mention that you'll need to make a corresponding
theme park reservation to go along with your valid
theme park ticket. You can make your theme park reservation for the park you choose to start in, and it sounds like you have
Park Hopper tickets which is great! After 11:00 AM (pending availability) you'll be able to easily cross over to the other park to enjoy the best in both parks in the same day. Both parks are located so close together, it makes it very easy and convenient to park hop, and you'll get to enjoy double the fun!
I hope this information is helpful for your trip Kelly, and I'm wishing you and your family a magical visit! If we can help with anything else,
please come back to planDisney!
Have a magical day,
Melissa