re: Best Disneyworld activities for toddlers.....

At Magic Kingdom, I hope you already have FP+ for Anna & Elsa, because if you don't you're screwed.

Because you won't be able to do things like Space, Splash, Thunder, Mine Train, Barnstormer it kinda opens you up. I'd still arrive early, but head straight to the Merida Meet & greet...probably one of the better ones and very interactive. After that, do some of the things that will build longer waits after 10 am..things like Peter Pan, Enchanted Tales with Belle, Pooh, etc. Make sure you see the festival of Fantasy Parade. It starts in Frontierland and I like to watch it near Pecos Bill. There are some areas with shade and instead of dealing with people lining up at 2 pm for a 3pm parade on main street, you can usually find a spot in Frontierland about 2:45 and get just as good (if not better view).

If you have some extra $, the wishes dessert party at the tomorrow terrace is nice. The food is blah, and it is overpriced like everything else, but it is cool to a private section with a photopass photographer.

Main Street Electrical Parade is another great usage of a FP+ if you choose not to do the dessert party. It has a perfect location for the parade and castle projection show afterwards, BUT the view for Wishes isn't the best. The castle actually blocks some of the fireworks.