The Wizarding World of Harry Potter

I’d say Diagon Alley is the most immersive, but Hogsmeade has the best rides More on reddit.com

Ministry - Never seen an attraction with the unleashed imagination and scale this one has. And it has a really strong ride story, too. Pretty much the ultimate Universal ride! Hagrid’s - It’s so good it makes any wait however long worth it! The storycoaster elements are great, but even without them, it’s a (dragon)fire ride! Forbidden Journey - I’ve grown to love this one even more the past several months. I don’t get motion sick so this one hits just right to me, and I love to peek outside the RV to see how they pull everything off. Just really cool! Gringotts - It’s everything it needs to be while making the most of a small space. The finale needle drop hits just right but these days I wish it didn’t brake in front of screen scenes so often and had more moments like the final launch. Hippogriff - It’s here! More on reddit.com

There are Harry Potter areas in each of the two parks. The biggest thing is that you need Park-to-Park tickets in order to ride on the Hogwarts Express (train that takes you between parks). There is a mini show that happens on the train, and it's different riding in each direction. More on reddit.com

First, I’m very jealous that you get to experience this for the first time. Second, answers to your questions: Yes this is the correct ticket. You will have plenty of time to go through the entirety of both Harry Potter sections in one day in both parks including the Harry Potter rides. All of them are must ride. Now, if you want to additionally explore the non-Harry Potter areas of the parks in one day-then you might be crammed. I recommend exploring those parts as well by the way ! Go to both, especially if the Harry Potter sections are the only ones you are interested in exploring. More on reddit.com