Reach the fourth checkpoint on the Sidewinder Canyon track. Then, pass the bridge and quickly turn right when passing through the barricades on the right side. Now drive along the dirt road and stop after the first bridge. Turn right to reach another bridge and drive until it ends. A checkpoint labeled "Pit" will appear. Enter that checkpoint to enable the bonus track.
Set the weather to "Snow" and begin a game on the Breakneck Ridge track. Then a hockey puck will appear in the icy area of the track.
Drive on Breakneck Ridge track with clear weather. Then, dive into one of the lakes or ponds and set your view to see underwater. A giant hockey puck should be sunk on the bottom.
Drive on the Scrapyard Run track and drive until reaching a set of railroad tracks. Then turn left at the tracks and follow them until the drive-in movie theater appears on the right.