While most of my shots in the Wizarding World of Harry Potter are taken after the park has closed, as I wait for the perfect time to get my last ride in I naturally still walk around to grab photos.
I often get asked how I am able to come back with captures that don't have people in them, and it's actually pretty easy.
If the park closes at 7, they have to let you enter any ride up until that point. So we make sure to be at the Wizarding World by about 6:30, hang around until 6:55 or so and then have one last ride on Harry Potter and the Forbidden Journey.
By the time we get off the area is, incredibly enough, EMPTY. There are usually no more than 4 or 5 people hanging around and at that point, even without long exposures, you're not going to have anyone in your shot. Security is often very cool about letting you hang around and will even offer to help you take a shot. The general rule is that as long as you're not walking AWAY from the exit, you can take as long as you need to (within reason, obviously).
It's a pretty dramatic difference from say, 12pm, when the area is absolutely packed.