In 2014, San Francisco started the postseason as the second Wild Card. The Giants' win in Pittsburgh behind Madison Bumgarner began a run that ended with a Game 7 victory against the Royals to win the World Series. It was their third title in as many playoff appearances for the franchise, so even though they are once again starting on the road, it is a path they are familiar with.
Much of that has to do with personnel. There are several players, starting with Bumgarner, who have been around for all three of those World Series titles.