Ive never lined up to watch the parade. We usually just stumble upon it. It’s never seemed hard to find a place along the route to watch.
The Mardi Gras parade is different. If it’s during Spring Break people stake out spots along the route early. You can always see it last minute as well, but to be up front for the beads, I’d say 30 minutes to an hour depending on crowd levels. It doesn’t run in August, but I figured I’d mention it for others who might be curious.
We’ve never felt the need to get to the shows super early. They don’t seem to fill up as quickly as Disney shows do. I think the previous advice you got on those seem good.
We went and watched the new nighttime lagoon show the other week. We went to the park that night solely to see this, so when we arrived at 9, I headed straight over to the viewing area in Central Park. At 9:00, 45 minutes early, I’d say it was already about 1/4 of the way filled up. I wandered around for a bit trying to figure out where would be the best place to stand. I was told directly across from Starbucks, and that seemed right. That location puts you in the direct center for the show. By the time I figured this out at about 9:15, this area was already taken along the rail. If you were tall, I’m not, you could have stood behind people, but luckily a nice family said they had room for me and my sister to stand with them. You could still definitely walk up and see this show up to starting time and even after, but if you want the best unobstructed view, I’d arrive early. Also, you do have to be on the Central Park side of the lagoon to see the show. You can see some effects from other locations, but the show consists of movie clips projected onto a water mist. That’s not going to be visible from the other side of the lagoon.