In reply to Ben Watts:
I think I'd start at Dunmail Raise as it's the one road crossing with nothing there. Assuming you are going clockwise then:
Day one is to Wasdale and possibly a bit beyond. There's a water supply between Yewbarrow and Red Pike to the south of Dore Head plus a couple of tarns further on beneath Red Pike.
Day two: from there to the Keswick area. You can resupply either in the evening if you are going well or in the morning if you aren't. There's places to wild camp as you drop off Robinson around Scope Beck
Day three: depending on how you feel and how far you got the previous day, you could have two shortish days split near to Threlkeld or one long one to get back to the start.