I'll get me down to some lonesome valley, No man on earth there shall me find. Where the pretty small birds do tune their voices, And never blows the boisterous wind.
This from my school days (1950's) in Bedfordshire.
Our music teacher interpreted the "lonesome valley" as the grave.
The "banks" of the sweet primroses could be the furlong head banks where the plough was turned. These banks are still to be seen in Northamptonshire and Leicestershire where the ridge and furrow was grassed over for sheep walks. In May they would have sported primroses and cowslips. As Milton tells us "...May, who from her green lap throws, the yellow cowslip and the pale primrose."