I'm going to be a smartass in a different direction:
Since the piece of cheese couldn't weigh that much and a mouse is small, put the cheese in your pocket, the mouse on your shoulder, and the cat in the boat and row everything across at once.
![Grin](http://saberforum.com/Smileys/default/grin.gif)
This puzzle usually has to do with weight or size issues of the capacity of the boat.