I have to agree with the folks suggesting a PTO tiller for the tractor. One year we tried a rear tiller which was belt driven on my friend's Toro. It was awful. Main problem was that you had to shut down, get off, dig stuck rocks out of the tiller, and so on. Even relatively small rocks would jam it up. I've also used a very small walking tiller, and had the same problem.
The PTO tiller I have now is a joy. If a rock does get stuck, which is rare, you just disengage the PTO, raise the tiller, engage the PTO once or twice and the rock simply falls out. I have never once had to manually remove a rock from it. This alone makes it worlds easier, but it doesn't stop there. It's much easier on the body, and it's much faster. I can normally till in 5th gear (out of 12) and do a pretty good job with one pass. If there is heavy sod, I'll go down a gear or two, of just make a couple passes. It's a whole different world having a good PTO tiller!