There are no tussocks around here; but we have got public footpaths across the middle of arable fields. Being among the first to use the "path" after the field has been ploughed is a reasonable substitute for training over tussocks.
I am with Travs on Snowdonia being the best fell-running terrain south of Hadrian's Wall. But I am appalled at his negligence in not including Moel Cynghorion in his pre-Peris warm-up, to do a complete "Reverse Moel Eilio Ridge race".