WHAT: "The Happiest Homecoming on Earth," the 50th anniversary celebration of the opening of Disneyland in Anaheim, Calif. Anaheim is 27 miles south of Los Angeles and 100 miles north of San Diego. * WHEN: The 18-month fete begins May 5 and runs through October 2006, which means there's no rush to get there -- especially since Disney sources concede that, just like 50 years ago, not everything will ...