Last year we took our DD who turned 2 on the trip. She didn't nap that day due to the excitement, and ended up falling asleep around 9:00 pm, but from the minute we walked in around 3:00 she was dancing to the music and had a huge smile plastered on her face.
At one point we stopped trying to hit the treat trails because all she wanted to do was dance. She picked a good spot out of the way of traffic and danced and danced for a good hour. She was so enthusiastic that passersby stopped and watched her and quite a few even joined her for a few minutes!
My DH and I took her back to the hotel and she stayed with my mom while he and I went back to the park to ride rides and trick or treat. We all had a wonderful time, so much so that we're going back again this year!