Bought Nintendo World Early Access tickets yesterday and took my son for his first visit. The park opened yesterday at 9 am and Early Access was 8-9.
We were at the park gates maybe at 8:05 am, but by the time we got down to the Lower Lot (they checked our Early Access tickets three different times, and scanned them at the top of the StarWay), the lines for the Key Challenge games were already 20+ people long, and by the time we went through the Mario Kart standby line and were off the ride, it was already past 9 am general opening.
I tried making reservations online for Toadstool Cafe, but it didn't seem to open until after 9 am. By the time I checked when we were about to get off Mario Kart, everything was booked through 3 pm.
We ended up getting back into the Mario Kart line via single rider, playing the Thwomp and Bowser Jr. games, and then going around and hitting blocks. We didn't stay past about 10:30 in SNW. We rode Jurassic World (it was his first time on the ride), visited Secret Life of Pets (the line moved so slowly-- the team member said it was because people took a long time getting into and out of the vehicles, and dropped stuff on the ride), and went to see WaterWorld.
I think my son enjoyed it, but he said it was too crowded and it wasn't a good thing that EVERYthing in the land required waiting in a line, including to hit the blocks with the power bands. He was in Orlando for his spring break with a school group and visited both Disney World and Universal, and he said Universal Studios Hollywood yesterday was more crowded and less fun than the Flrorida parks during spring break season.