I think it is more about picking the right line. You must carry your speed through the turns and up the hill. If you screw up the line 3 turns back the guy behind you will carry his momentum up the hill and slingshot right by you. The karts lose all kinds of speed if you take turns too tightly and they have no torque to get you back up to speed on the exit...so you basically have to pick the widest route around the track.
The tough part is passing though. There is really only one line around the track and the only way you get your nose out is to lay back and hope you can negotiate the turns before the hill better and pass mid-way up the hill... or stick your nose out on the inside line to the hairpin downhill, slam the brakes, and block the other driver LOL! I did that with my cousin...it was great. Of course then we almost got passed by my other cousin because we lost all momentum.