Ballybunion New was the toughest walk I can remember, also National is uphill for 17 and 18, I remember playing it in August, 95 degrees and the walk up 18 was brutal, there was another course in New York, I can't remember its name right now, but when I took off my golf shoes, I had blisters on each and every toe from walking uphill, my toes must have assisted my gripping, never happened before or since.