Hook up a second controller and do this locally on the Worcestershire level. Do the boosting account first and try to avoid the coins. If you miss all the coins you'll get a score of around 5500 which is really easy to beat. On your real account, pick up a few coins to get the multiplier to 3 or 4x to ensure your victory. You can replay the first level (don't advance) and each time you see the "winner" screen it counts as a victory.
Make sure you pick up 3 potions at some point to get the dronkey achievement. There's only two potions per level so you'll have to spread it across two levels.