This page is for hints on the Career Mode's race tracks and challenges. If you were looking for the story walkthrough, come here.
Game34rules has written a mini-guide for beating this payoff:
If you can't beat this Payoff, I know how. Get as far ahead as possible between the start and the end of the second hill. Drift and draft as much as you can. After the turn on the second hill, and there will be a little opening between a sign and a tree. Aim straight for it and use your drift boost on it. Don't make you self land back on the track! You will get about 600-800/ airtime points, then as soon as you land press the SELECT button to destory your kart. Go the dirt shortcut (dark brown) and turn RIGHT into a hidden path with a huge jump, then go over the turbo pad and press the X Button to jump higher. You should get about 800-1100/ air time points. Follow the track and earn up more drift points DO NOT GO UP THE BIG HILL AND OVER THE LEDGE! Instead, take the middle path and on your RIGHT there should be a ramp. Go off it using your boost and pressing the X Button at the end. That should give you about 100-150 more points. The last lap is where you should be able to skip the first jump to save time, ONLY IF AT THE FIRST JUMP OFF LAST 2 YOU REACH 3000 AIR TIME POINTS! Otherwise go off the jump and do the best that you can.