On super busy park days, your FastPass+ isn't just cool, it's a freaking golden ticket, but if you couldn't get one for a popular ride your kids just have to experience (think Slinky Dog Dash in Toy Story Land, Avatar Flight of Passage in Animal Kingdom, and Peter Pan's Flight and Seven Dwarves Mine Train in Magic Kingdom), make that your first stop of the day. Even if the line is already long (and it probably will be as many other people will have this same plan), it's guaranteed to get much crazier throughout the day.