Note: You cannot do this with a silver account.
I would suggest trying to beat the long jump challenge on Devil's Playground. Use the bonus ATV and warp to the "grass hills" marker from the pause menu. Turn around, go Southeast and hug the right side of the mountain ridge to find the jump. You should land near the water where the rock arch is located.
Get a good run-up, keep you wheels on the ground and use the seat jump to get more distance (push right stick down and click right before you jump). The best I got was 311 feet (95 meters) and the worst was 285 feet (87 m).
If you don't have any friends who play this game, go play a couple games of multiplayer, send friend request to some higher level players and tell them you are trying to get the achievement.