Just got back last week with 2 little ones, 3 and a half for our older son, 14 months for the little guy (about to turn 15 months next week!). They normally go to bed between 7 and 8 each night at home.
DS3 never naps at home but he did at Disney. We got to the parks before rope drop, left by 2PM each day, and a couple of days he fell asleep in the double stroller toward the end of the day at the park (some time after lunch he would fall asleep). He normally is not in a stroller either, but we knew we would need it at WDW.
DS1 sleeps anywhere and did so at Disney too.
We were in a room in the 50s section at the Pop Century and had a great view of Epcot's fireworks each night at 9PM. DS3 watched every night, and then went right to bed, had no problem getting up early in the morning! We woke him up around 6AM the earliest, 6:30 the latest.
So he did adjust. He was so enthralled at Disney that he did fine! Both kids behaved very well in restaurants, at the parks, at the hotel. My kids are normally very well-behaved, and we do take them to restaurants once a week, to other people's houses all the time, and many other places. So I knew going in that they would be okay at Disney, but still had my worries. You know your own kids best, so always do what is best for them and you will have a great time!
BTW, I would never go to Disney without my kids! Just my own feelings, not judging what anyone else does. But I don't think I could ever go there without them! Not until they are grown and out of the house!