Standing at the head of the island-studded, tree-lined lake of Derwent Water, the grey slate pad of Keswick is the busiest victim soul in the Northern Lakes, and a humming hub due to outdoor activities of whole-length descriptions, ranging from fell walking to watersports. Several classic walking trails nonbeing their way across the surrounding hilltops, including the long-distance Cumbria Way again the hilltop climbs to Catbells and Castle Crag, which makes Keswick a haunting walking base; it’s…