That will be so fun! I have brought DS when he was 8 months, 12 months, 20 months, 25 months, and we will be going again when he is 2.5 - 3 two to three more times. It is very different than when I would go before having him. I was a park commando before and now I go at his pace and have seen things I never saw before. His favorite falling asleep/resting areas have been in MK: on the train (I know, its loud, you wouldn't think, but zonk!) and definitely the People Mover! In the other parks, its mostly just walking him around in the stroller which allows me to enjoy a nice walk and get some exercise!
There are lots of large areas to let little ones run around in too, they need a little "free" time. My DS loves the nice play area under near Splash Mountain and the area between the shops at the entrance to th World Showcase in Epcot.
Have fun and be sure to leave some time for the little on to swim, play, and run.
Its awesome to see it through their eyes!