Start with your resort's transportation
If your hotel has bus transportation, the bus or a rideshare are options to consider. Staying at the Contemporary, Grand Floridian or Polynesian? My recommendation is the monorail, with walking from the Contemporary as another option. How you arrive is worth sorting out before your park day. My full client guide explains the Magic Kingdom rideshare drop-off distinction and the other transportation options in my notes.
Give your morning a direction
If you're taking advantage of Early Entry, my suggested route begins in Tomorrowland and continues around the park toward Adventureland. If you're entering after the park opens to the general public, start in Adventureland. Choose your starting point, then keep your next stops connected instead of repeatedly crossing from one side of the park to the other.
Keep your park plan connected
Jumping between lands uses time and energy. Use the map in My Disney Experience to navigate, and keep that same route in mind if you're using Lightning Lane. You'll purchase your own passes in the app. The route matters for a family with teenagers just as much as it does for a family with younger children.
Build in a real break
A break can still be part of your Magic Kingdom day. My suggestions include quick-service dining as a place to pause, along with air-conditioned attractions where you can sit and enjoy something together. For families with teens and young adults, those stops are useful too. You can keep a day focused on the things your family wants to do while making room to rest.
Think about your evening
If Happily Ever After is part of your plan, viewing location matters. The fireworks and the castle projections are different parts of the experience, so consider what you want to see when choosing where to watch. My client guide includes my parade and fireworks viewing notes, plus the smaller details and photo stops I suggest looking for during the day.