If you really want to leave the outside world behind, the remote valley of Ennerdale is definitely the place. Just to the north of Wasdale, this valley and its namesake lake were once home to slate mines and large timber plantations, but these are slowly being removed and the valley is being returned to nature as part of the Wild Ennerdale (www.wildennerdale.co.uk) project.
Needless to say, the valley is paradise if you prefer your trails quiet. Several popular routes head over the fells to Wasdale, while walking towards Buttermere takes you past the Black Sail YHA, a marvellously remote hostel inside a shepherd's bothy. Much loved by mountaineers and hikers, it's become a YHA landmark. Space is very limited, so make sure you book ahead.