This trophy is a bit frustrating. Home of the Padres, you'll see a group of stands just to the right (looking from home plate) of the dead of center field. In front of the stands is sand, and that's where you have to land the ball (just over the wall). It's probably somewhere between 400-410 yards.
Home Run Derby is the way to go: I used a right handed hitter and just kept trying to be a touch late on the pitch. Eventually I gave up on swing strategy and just started hitting homeruns until eventually I got lucky -- I'm not sure there's much more to it than that.