I used a covered catbox and this mat at the front that Bean Bean steps on when he comes out.
It doesn't get it *all* but it certainly catches a good majority of the litter that is kicked and dragged out of the box. My cat enjoys digging to china in his box.
The good thing that I like about this mat is that it has little rubber things that poke up and help to brush the litter off your cats feet, and then it is trapped down a little ways into the mat itself.
It's very easy to shake it off outside once or twice a week, just like a carpet. And Voila, it's ready to use again.
I think they sell them at most pet stores for under 10$. I got mine at petsmart.
Edit - I forgot to mention that my cat also likes to use it as a scratching mat.
And he curls up and lays on it whenever I am in the bathroom too.