You're supposed to arrive at the restaurant 15 min. before the reservation. I would take that amount of time and add some time to take a few pics by the castle & on Main Street while it's relatively crowd free. I think you would be fine going in 30 min. early. We have never had a CM check our reservation time when we entered through the early breakfast entrance. You don't want to enter too early because there really isn't much else you can do other than take a few pics. Everything is roped off so you won't be able to ride anything. Be sure to take advantage of getting there a tad early to take some pics without a lot of people in the background, though. It's priceless!