Can't argue with Paul's suggestions
Just to add that Corney Fell (time it so you don't meet Sellafield commuters!) and Birker Fell are worth it as well. My playground as I can be there in about 15 mins
Any of the moorland routes south of Eskdale are good, and even on hot sunny bank holidays you will hardly see anyone up there.
On the other side of the coin, I was heading up Wednesday afternoon to meet up with a (retired) tosser in Keswick. I thought it's term time and midweek so I'll go Newby Bridge, Windermere, Rydal rather than my usual Greenodd, Coniston, Rydal. WRONG CALL, traffic and roadworks were/are horrendous daytime, it took me about an hour to get 30 miles!
Coming back around 9pm it was fine, about an hour to cover 50 miles.
Have fun
ps Beware the three T's................
Tractors, Tourists and Tankers, all of whom have a tendency to stop in the middle of the road just around blind bends.......