In reply to kcraig85:
Did it the other way round when I was 16. Took three days with camping gear starting at Millom, over Black Combe to Eskdale camp. Next Burnmoor to Scafell, Scafell Pike, Esk Hause then Borrowdale camp. Had planned to do the Derwent fells but the weather was bad and was tired so just went over to Watendlath then down the road to Keswick. Without camping gear using hostels we would have done it in two days, but at that age we felt we did well.
If you are fairly fit and familiar with the route it should be OK, the road bit at the end could be hard on the feet though if it is wet.