We took our twins 6 times from when they were 18 months to just before they turned 3 so it can't be that bad with a toddler right? Only on one trip did we have help and we made it and had great trips.
First and foremost, either bring or rent a good stroller. Very important. I recommend something with a full canopy and a good recline. For that age, don't even consider renting one from WDW. Some people recommend returning to the room for naps. I can truly say that did not work for us at all. Always a fiasco. We usually let the boys sleep in the stroller and if we wanted to break from the parks we left after they napped. You will have to see how your child does because they are all different. Mine would just be too wound up when we got back to the room.
Do not underestimate a playground. Wonderful for the littles. Get to the parks for rope drop every morning and you can do so much the first hour, especially in fantasyland. Follow the recommended parks from a site like easywdw.com. Crowds and lines are not your friends with a toddler. As for staying out late, you have a helper so that may help you all. We just can't do it now with ours.
As for sleeping, you don't say where you are staying. I would sleep your baby in whatever she is used to sleeping in. Mine were great in pack n plays because we travelled so much. If she sleeps in a crib then rent one from an offsite company (I like ABBF a ton).
Bring lots of snacks and whatever she is used to drinking out of. Finger food snacks helped us many times waiting in lines.
If you have more specific questions ask away. I will be glad to offer any help I can. I promise, it will be a great trip.
This is great advice. We took DD when she was 9 months, 21 months, and just got back from her third trip when she was 28 months. The 21 month old trip was so fun. I agree get a great stroller. I highly recommend the City Mini. We always rent one as we don't own one at home. Even though DD doesn't nap in our stroller at home anymore, she will nap in this one. It has a great canopy and reclines. We hit the parks at rope drop usually. We dont leave for naps because DD won't nap in the hotel room, but she will nap in the stroller. After lunch, we put her in the stroller and walk around until she falls alsleep. Then we take turns riding the attractions she can't ride. We will often grab FP for those in the late morning if they have return times for around naptime. She will usually nap for a couple hours then we keep touring. If we want to go back to the hotel early for swimming, etc. we also wait until DD has napped.
DD never really slept very well in a PP at home, but at WDW she was so tired, it was not a problem. This last trip, we let her sleep in other bed as she now sleeps in a bed at home.
If we want to do the night shows, we can sometimes push DD to stay awake for them. She usually does ok until about 9:30. Anything after that and she is asleep in the stroller. We have done opening to close with DD before. If we do that, we usually get DD sleep in the next day instead of making rope drop. More often, we leave around 6-7 and go back to the hotel.
As for food, I usually try to order something DD will eat so I don't have to buy her a meal that she won't eat. Sometimes, we will get one adult and one kids CS meal and all share (DD, Dh, and me).
Also use the babycare centers if you are nearby. Most of the bathrooms only have 1 changing table, which is ridiculous. Most of the babycare centers have alot of changing stations, which makes it a little easier. Plus, it is a place to get 5 min. of quite if you need it.
It is alot of fun doing Disney with them at that age. They learn so many new words and pharases while there. They are so exicted. You will have a great time.