Ian, you can run from East Grinstead to Groomridge e/w for approx 10mls along a disused railway track. No hills I'm afraid, perfectly flat and you'll return the same way unless you can find other F/Ps to return by. Walked it many years ago, it's a lovely off road run. I'm sure you'll find local maps in East Grinstead when your there. Is it this week?