However, there have been a couple of levels so far which my solution of, while working, and collecting all bonus coins, seems to have been completely 'wrong'. Could anyone tell me how you are supposed to do these levels?
[Warning: Spoilers!!!]
Foggy Mountains / Base Camp:
I use Stinky with the boulders to kill Kaboom!s, then I collect the bonus coin by the Coily and block the coily in with a wooden box. Then I use Stinky to put 1 wooden box into the corner of the water opposite the message+key in Loof's area, and the same in Qookie's. Imagine my surprise as I switch to each of them, complete the bridge out with the wooden box from their own area, and find the message under the key obviously intended for Stinky - I have not managed to find a way of solving the level which involves Stinky being the first to see either text.
But there is another surprise waiting for me... I switch to Peegue, and see a text saying that he needs help. However, as long as I have collected all the keys in the lower area beforehand, Peegue is able to complete the top area on his own, and get to the gold star without ever meeting the others!

Fire Island / The Volcano:
Here, I am left with 3 completely unused steel boxes, and 1 unused wooden box, at the end... also, I notice that there is some floor hidden in the volcano which could perhaps be used to get the bonus coins without using the secret passage, if there was another steel box? I push the boulder off the conveyor button and step off myself. Once there is a boulder on the red button, I step on the conveyor button, and off again once the boulder on the conveyor has entered the lefthand side. Then I go and wait by the blue gate. As soon as a boulder is stationary on the blue button, I hold down the left arrow key, going through the teleporter and stopping with a steel box on the conveyor button. This is in plenty of time to stop the boulder on the conveyor knocking one off a button. I am now able to retrieve the 3 other steel boxes by pushing into the teleporter, walking in through the blue and red gates, and pushing out of the lefthand side of the teleporter. Now I release the conveyor button, destroy one boulder from a gate button, step back on the conveyor button and repeat for the other gate button. I then leave a box on the conveyor button, and take another to the top-left of the level, avoiding the remaining boulder. I collect the key and bonus coins, press the other conveyor button at the right time to dump the boulder into the lava, and then bring the steel box down and leave it on that button. I can then put a steel box on the pink button, use 1 wooden box to enter the island, destroy the Chomper and Kaboom!s on the electric floor, collect the remaining bonus coins via the secret passage, and then use two more steel boxes to reach the exit. Is there a solution that uses all the boxes (apart from pointlessly pushing them all into lava/water
