Hi Julia! Thanks for dropping by planDisney.
You must have a
valid ticket and
theme park reservation to enter the parks. Since you only have a ticket and reservation for Disneyland Park, you won't be able to enter Disney California Adventure Park without purchasing a
Park Hopper upgrade at the main ticket booths. You'd have to pay the difference and prices are subject to change.
I'm sorry if that's not the news you were hoping for! I certainly understand wanting to dine at Lamplight Lounge. It's one of our favorites and many other Guests love it too! It can be tricky to get a reservation there since they're snapped up quickly.
There are fantastic dining choices in Disneyland Park, however. You can choose between table serve and quick service locations, depending on what you prefer and what's available. Use the Disneyland mobile app's map and switch from Attractions to Dining at the top to see all the dining locations in the park. If you don't have a reservation for a table service location, some offer a Walk-Up List, which you can join on the app when it's available. Or you can mobile order your meal and get right back to the fun that much quicker.
I hope you enjoy dining today at the park!
Elizabeth