In reply to Tpgough:
Depends on your definition of walking distance really.
Bridestones (train to Todmorden, 30-45 minute walk up the hill).
Stony Edge (train to Walsden, 45 minute walk)
Blackstone Edge (Train to Smithy Bridge, bus/walk up A58)
New Mills (train to... well... New Mills)
Castle Naze (train to Chapel en le Frith, 30 mins walk).
Woodhouse Scar (train to Halifax, 1.5 mile walk)
There's plenty around the Hathersage/Grindleford train stations, I'm not an expert on the area's bouldering, but a train from Manchester to Llandudno/Conwy Valley doesn't take as long as you might think. Definitely doable for a nice day trip.