I have a 3 yr old daughter diagnosed at 13 mos. We live in Florida so we went a couple of times already.
We don’t carry the travel letter from her doctor to disney and we were never asked about her supplies. I always mention it to security when they check the bags but they just don’t mind about her pouch.
What I normally take is water, juice, glucose tablets (dex-4), tons of snacks (apples, cereals, cereal bars) so she can have a healthy snack between meals and if for whatever reason there are lines to buy food she can start eating something.
All of the times we went there her numbers got high just because the food they have at the parks is not the most healthy…
It’s a good idea when you have breakfast at the hotel to separate a couple of things that you can take with you (fresh fruit, etc) and save it for snacks.
When you enter the park there is a guest relations office but they don’t have anything special for kids with diabetes unfortunately. When they saw my daughter they were, she can stand in line (yes), can she wait (yes)…so nothing…but we as parents of a kid with type 1 know that having a fast pass or at least avoiding them to stand in the sun for long periods helps their numbers…
Plan on eating around 12 cause later there’s a lot of people at the restaurants and the lines get really long…
I don’t know the age of your daughter, but mine uses the stroller on and off, so it’s always nice to have a seat for her if she gets tired.
And last but not least, don’t forget your camera and enjoy !!!