Depends a bit on what you mean by easily accessible but there are loads in both areas where you get good views from the roadside. Any of the high passes in the Lakes, Kirkstone, Wrynose, Hardknott, Honister, etc give good views. In the Dales again a lot of the higher roads give views, The view of Ingleborough as you go up into Kingsdale is a classic as is the view from the top end of Chapel-le-Dale and over into Ribblehead. Garsdale and Barbondale over into Dent, are also good. The Dales is usually MUCH quieter than the Lakes and it's often easier to stop the car and grab a photo..