Don't bother with the cat....I have one and it just watches the mice run across the floor with a look on his face as if to say: "Get that, will you"...
We do use peanut butter -plus- a little bit of jelly candy stuck in the peanut butter. We also tie the trap to the drain pipe under the sink (that's were they end up) so they can't take off with the trap.
Hope this helps....