We went in September last year with our almost 3 year old and here's a few things we learned. Plan on taking breaks - we figured in September it would be cool enough to go for full park days, but we all needed the time to get out of the sun. Our daughter was a champ at the stroller nap, which we figured would be a better idea than back in bed with us awake - so try to figure out how your daughter naps best and plan that in (no one wants a cranky tired kid even if it means losing some time on rides). We actually didn't lose a lot of time for those naps though, they usually happened when walking to the bus and then on the bus, or walking around World Showcase. Order food through instacart or garden grocer or one of those others, and brings snacks and drinks into the park. I highly recommend a cooler backpack (we have one called arctic zone we got at costco and wasn't that expensive) to keep those drinks cold, as well as cooling towels. Try a stroller fan. Even though our daughter hated it (no idea why...), when she fell asleep we put it on to keep her cool. On that topic, while our daughter was "normal" during the trip, I can't explain and couldn't expect some of her behavior. For example, she couldn't stand rides where she thought she could get wet. This made sense for actual water, and she was ok on the Little Mermaid ride. But when it came to Nemo, she was convinced she would get wet. It took some getting used to when you spend months making plans, but you have to just roll with it a bit. For any dark rides, have your phone ready in your hand. Whenever she started getting nervous from the dark, I would just turn the screen on, and tell her to look at that, and she was ok. For characters, our daughter wasn't exactly scared, but more just uncomfortable with them (even face characters) for the first 3 days. Then all of a sudden she was great with them all, giving hugs, talking etc. I think she just became used to them, but my one regret is that Ariel was her favorite, and we met her the first day when she wanted nothing to do with her. Had we gone back, she probably would've been much better. Try to space out the characters, even if she doesn't do well at first, she may later on. Mentioning regrets made me remember one more thing - bring either ear plugs and/or headphones for fireworks. We somehow forgot them, and she was terrified. The music they pipe in was loud and just added to it. Even during the day at MK they do a mini-show with a couple of fireworks, and those even scared her. We went to fireworks last week and brought headphones to cover her ears, and she was fine.
Oh - and make sure you watch her face as much as you look at your surroundings. The excitement from a child's perspective is where some of the real magic is!
