Just before you reach the big hill prior to the overpass area, go directly into the wall on your left. Drive into it at full speed and jump as you hit it. If you do this in the right place, you will clear the wall and land just behind the three hills immediately behind the finish line.
Mario Kart 64 Shortcut Video Walkthrough Series for Nintendo 64
Mario Kart 64 - Choco Mountain Shortcut Video
