American Wasteland

Enter each map in Free Skate mode. When it loads, go the the Pause Menu and hit 'Start Run'. You have 2 minutes to get 2,000 points, which shouldn't be hard at all. Once you get 2,000 points, you can either select 'End Run' from the Pause Menu or play through the run. Quitting after you get 2,000 will not get you the achievement.

Note: Do these achievements before the Classic Mode ones, as you will have to beat your Classic high score for this achievement as well.