Set in one of the more remote parts of Northumberland, Kielder Water may be man-made, but it is a haven of tranquillity. This lovely stretch of water is surrounded by forest; at over 250 square miles, the largest working forest in England. The lake is a popular place for water sports, while the forest offers miles of walking and biking trails. It is a haven for wildlife, one of the few places in England where you can see red squirrels. And on a clear night its skies are full of stars, as this is an International Dark Sky Park with…