On the 1st selection screen type any of the following:
"SHEEPY SHEEPY" ---------- For a sheep as a vehicle
"TURBO NUTTER BASTARD" ------------------------ ???
"IDKFA" -------------------------- For auto qualify
(and access to 3 bonus tracks in single track mode)
Grassland 1 has a short cut - where you have the blocks in the middle of the road. Go just past there and you can drive through a tree.