I recommend trying to do this with the following settings:
Race: Lv.1 – Adrenalin Peak
Character: My Avatar
Board: Rare Board – High Top
"A" Rank reference score: 3000 points (Thanks Terrin)
The big trick here is to try and keep your combo going. For every balloon you get, your combo points increase and the next balloon of the same type will be worth the new point value assuming you can collect it before your combo meter runs out. For example, the first yellow balloon is 10 points, then 20, 30, 40, 50 and finally 60. Once you hit 60 each yellow balloon after that is also 60 points assuming you can keep your combo going. Once you break your combo you are reset back to 10 points per balloon. There are also red balloons and they start at 50 points.