Behind a stack of crates on the right side of the track.
Directly behind a bride column on the road. I believe you'll find it after the first elimination. It is NOT on the beach.
The hidden package on moon island elimination is behind the shed, in the 90 degrees curve to the right, before the beach.
In the middle of the first long left turn, there is a shortcut that goes by a windmill and some houses. There is a detonator powerup and the hidden package is right next to it.
its a hard one
Near the house to the left.
On the right beside a water tower.
After the double ramp on the right.
go after the gas tank in the forest and you see a track in right side and you see a hidden package
i dont know XD
Under the little bridge on the right
its behind the big rock before the finish line.
its above the 2nd ramp after the tunnel.