Instead of going up the track to Gatesgarth go through the gate to the right of the bridge at Sadgill and up on to Great Howe. You can then go on to Grey Crag, Tarn Crag and Branstree before following the fence down to the top of Gatesgarth and off up to Harter etc. If you want a bit extra, drop down to the head of Haweswater from Branstree and take the ridge over Rough Crag and Long Stile up onto High Street, over Mardale I/B then drop down to Nan Bield and up onto Harter etc. back to Sadgill. Did that route on Sunday with lots of snow still about and is a great run with a bit of everything.
Do a lot of my training from Longsleddale so to many routes to describe on here. Maybe give me a pm nearer the time and we could go for a run or two, depending how fast you want to go !!!