The Keys To The Mouse House

Sean Daly: LAKE BUENA VISTA

Walking with a practiced regal grace from Liberty Square to Frontierland, from the newly Obamafied Hall of Presidents to the riverboat home of Disney's newest princess, Kennedy Johnson is the very price tag of progress.

As her twin brothers keep Mom and Dad on swivel-headed alert, 5-year-old Kennedy is in a blissful dressup daze. She is begowned in a lily-pad-green dress ($90) and tiara ($20). She holds a doll ($17) wearing the same sparkly outfit and, a first, the same brown skin. She just left the Bibbidi Bobbidi Boutique, where wee royals-in-training get gussied up for as much as $190.

"This is a very important day," says Treza Johnson, 37, gazing down at her…