While on the Ranger Station and Uphill Drive (not off-road drive) levels, when you get to the sharp turns instead of making the actual turn, go up the mountain. While in 4-wheel drive, get to the road that you were going to drive to. Make sure there are not any guardrails in your way. Also, when you get up to those sections, when the road is straight, 2-wheel drive is somewhat safe. Try using it for more speed.