When we went to DL last our youngest was also 23 months. By golly I was getting one more trip in before we had to buy that 5th plane ticket!
Hands down his most favourite ride was the caterpillar one in DCA with the watermelon smell. I swear he must of rode it 15 times! He loved all the rides in the bugs life area! He also loved the Winnie the pooh ride, jungle cruise, small world and dumbo. Their is a really good link on the Disney website where you can click your approx childs age group and they will suggest appropriate rides. We took him on POTC and he was a bit scared but covered his ears at the scary parts. We also took him to a character breakfast and supper and he really loved that. They really take the time to be quiet and gentle around the younger ones.