As for the flight, bring plenty of snacks and toys to play with. Try and buy some new small toys for the plane and don't let him see/play with them until you're in the air. The pressure may hurt his ears so have him drink on take off and landing, that should help.
He can go on any rides without a height requirement, and will love all of the rides in Fantasyland as well as others.
We had a freezer in our room, so we would fill sippy cup 1/2 way and freeze overnight. In the morning we'd add the rest and it took a while for the ice to melt.
I would plan on touring based on his schedule. If he can nap in his stroller, then that would help since when they're in the World, they could fall asleep at anytime since they're on the go so much.
Have a great trip!
Nancy
Good luck and have fun.