Plot: Today’s guide is 45-year-old life coach and all-round action woman Teresa from Longhirst. She has done half marathons, a full marathon, Tough Mudder and a cycle all the way to Edinburgh, so what sporting surprise has she got in store for our walkers today? She is taking them to Kielder, in the west of Northumberland, England’s largest forest, with over 200 square miles of trees