Oh dear - it looks like I was right and it was a bit too tricky for kiddies.
Maybe I should post it as well on the Puzzle/Action forum as an easier one for people who wouldn't think of visiting this part of Wonderland.
Well kids of all ages, if you want to get the boat across to Loof, have Stinky build his bridges.
3 boxes down to the boulder island
1 box down to the bonus coin
2 boxes right to the boat
Walk down to the boulder island and push the boulder up. The boulder is sitting on a conveyor button, so as soon as it rolls up the conveyor starts and the boulder goes straight onto the boat and takes it to Loof.
Hope that helps. If you need more, just yell!