It's one of the few areas I've never visited properly. Never got further down the valley than Cockley Beck, and no further up than Ulpha coming the other way. I have ran over Green Crag and Harter Fell, but from the Devoke Water side and dropping down into Eskdale.
Would love to do the Duddon Fell Race as well, but it comes at a particularly congested time of the year!
Stayed in Eskdale, just round the corner from the village shop in Eskdale Green. Fantastic for running/walking, so many great start points.... Birker Fell Road, Boot, Woolpack, Brotherilkeld, Wha House Farm. One of the nicest runs I did was almost a reverse of the Eskdale Elevation fell race, starting at Wha House, up onto Slight Side and Scafell, down to Burnmoor, missed out the Screes and dropped down to Boot. Wild and lonely ground all the way. Fantastic. And not forgetting the Upper Eskdale/Lingcove area, absolutely wild around there. Although I found to my cost that it's a lot easier to follow the South Ridge of Esk Pike towards Lingcove, than to drop down to Ore Gap/Green Hole, that was a particularly arduous route choice, but very quiet (not surprisingly).