It's not an official plan, but we had a very successful tour of Fantasyland during moderate crowds in May. You can see my trip report ("Magic Kingdom with 2 Pre-Schoolers") for more details. Here is what we did:
Arrive prior to opening. When ropes drop, proceed directly to Dumbo. If your party is large enough, have one person scout ahead to check waits for Peter Pan and Pooh. Have him/her get fastpasses for everyone in your group for whichever has the longest posted wait. Ride Dumbo.
Ride either Pooh or Peter Pan (whichever you don't have FP for). Ride the Carousel. Should be return time for your first FP attraction (either Peter Pan or Pooh). Prior to riding, grap FP for your group for Mickey's PhilharMagic. Ride Peter Pan or Pooh with your fastpass. Use the cut through by the castle to go to Storytime with Belle. If show times don't match up, you can use this time instead to greet any characters who are available nearby (Ariel, etc.). Return and see Mickey's PhilharMagic.
We followed this plan with one bathroom/snack break and did all of Fantasyland in about 3 hours with 2 3 1/2 year olds with no waits longer than 20 minutes.