The Ultimate Packing List is really very good, as is this one, but I've made a few changes to it based upon our family's needs. Some of the items on the lists are overkill (For example: why do I need to pack a portable high chair when the restaurants have them? Do I really want to be lugging that into the park? Even when we stay off site, we use our stroller as a high chair if we need one. Also, why bring walkie talkies when I get decent cell coverage and I can text my DH?). Other items we just don't need, like a corkscrew, wine stopper or pre-measured coffee and coffee filters. (We don't drink alcohol or coffee.)
Then there are the things that are left off of those lists. Itineraries for my ASD kids who need to know where and when things will happen (like which park we will be on a certain day and where we will be eating). Hair detangler for Princess Ballerina's really long hair as well as autism awareness shirts and/or cards. A lanyard with large plastic holder for the Guest Assistance Card.
Another item--when Whirlwind (and Acroboy) were younger, we brought our Child Safety Harness. Whirlwind was notorious for running off at lightening speeds, and it wasn't always possible for me to sprint after him (like when I was holding the baby). We had the same problem with Acroboy running/wandering. A friend gave us a Puppy Harness Buddy which looked like this. Acroboy like the stuffed animal version of a child harness I think in part because we treated it like a lovey when it wasn't in use. (The tail can disconnect).
Other thoughts about our list:
A small roll of duct tape has proven useful quite a few times as well. Alternatively, you can wrap some duct tape around a permanent marker or sharpie which comes in handy when needing to mark identical souvenirs, or using as a pen for characters like Mickey to sign autograph books.
On some trips we opted to take Sunday off and find a local church/meeting house, so we have dress clothes on our lists. Unless you are doing the same, have reservations at one of the dressier restaurants (like Victoria & Albert's) or are going on a Disney Cruise with a gala---you don't need them.
For bug repellent we use the disposable wipe kind, and I always bring a tube of Afterbite with us. Pool shoes are a must for the pools and or rafting rides in the water parks. (You have to take them off on the slides). My son and husband both forgot theirs this last trip and ended up getting warts on their feet. Pool shoes stay on in the lazy river whereas flip flops can break if you try to wear them under too much water. (Speaking from personal experience).
I have a special water bottle lanyard/carrier with a pouch. It is great for carrying my phone, camera, ticket/key card etc. you can get one here. Mine is different than this one, but it is the same idea.
Two pairs of walking shoes allows you to switch and give your feet a rest from one.
Zinc oxide ointment (diaper ointment) can help chaffed legs as well as talcum powder.
Garbage bags can serve as extra laundry bags, hold wet clothes, act as additional rain ponchos, etc.
Ziplock snack or sandwich bags can keep money, room keys, ticket and credit cards dry and together inside a larger bag.
Tissue packs and/or wet wipes for every person's fanny pack is a must for our family. Especially when some of my kids can't stand sticky, gross feeling hands.
We recently purchased some of those reusable water bottles with filters
in them. We are considering bringing those to the park now too in lieu
of disposable water bottles.
We have a data transfer cord to hook our camera up to my husband's laptop to transfer photos when the card gets full. You could just take an extra memory card instead.
Additionally, I gave each child a personalized list of what they needed
to make sure they packed it. Creating opportunities for them to be in
control of various aspects of the trip seems to help them enjoy the
experience more. We also have each child use a carry-on suitcase of
their own--with the understanding that I may require some room for
consumables we will use up on our trip.
We also bring a small journal to record our thoughts each day about our trip.
Lastly, we pack a separate suitcase just with snacks. I
pack the snacks I know I can buy at home cheaper than in Orlando AND it
serves the purpose for providing room for souvenirs to travel home. You
can have heavier items delivered to your hotel room. Just web search
grocery delivery Orlando, or better yet if you are a Costco member you
can order online and have it "shipped" to your hotel. (This is a good
option for obtaining a case of water if you don't have the reusable filter kind).
To see pdf versions of my individual packing lists follow the links: 11+ year old boy, girl, 3-10 boy, girl, and 0-3 boy & girl
Complete packing list here: