Thousands of fans in Giants gear who were eager to cheer the World Series champions in rainy downtown San Francisco grabbed prime viewing spots early Friday, hours ahead of the celebratory parade expected to draw up to 2 million revelers. The parade will feature double-decker buses carrying the players and floats of the Golden Gate Bridge and a panda in honor of third-baseman Pablo Sandoval, whom teammates have nicknamed ''Kung Fu Panda.'' Iris Gomez, 37, arrived to the parade route with sandwiches, juice and plenty of rain gear more than 5 1/2 hours before the start of noontime event. Rain was falling along the parade route Friday morning. ''I've been going to the Giants games since the tickets were $8,'' ''I wouldn't miss this.'' The parade starts at Market and Steuart streets and then heads to San Francisco City Hall and Civic Center Plaza, where Mayor Ed Lee will honor the team with a giant onstage ceremony.