The title comes from a short story about two hikers on a camping trip. They decide to cast off their clothes and walk through the countryside as nature intended, only to be mistaken for poachers. The story’s combination of humour, transgression and ear for the Doric dialect of north-east Scotland were characteristic qualities of its author, Nan Shepherd (1893-1981), a writer unashamed by her nakedness and celebrated for her evocations of Scotland’s rural environment.

Celebrated, that is, once The Living Mountain, her short book about walking in the Cairngorms, was published. That was in 1977, three decades after its completion, but more especially in 2011 when it was republished by Canongate, just as it was slipping back into obscurity.

It had not always been that way. As the author of three interwar novels, Shepherd was considered a significant modernist writer in her day. But, having turned her attention to teaching, not to mention roaming the hills, she had been largely forgotten at the time of her death in 1981.

As this one-act play by Richard Baron and Ellie Zeegen would have it, she is a woman with little concern for posterity. Played by Susan Coyle, Shepherd is resistant to flattery and modest about her achievements, coming most alive at the sound of poetry; sometimes her own, just as often not. At times in Baron’s production, she asks members of the audience to read her favourite passages aloud (which, at my performance, they do impressively).

Part of a generation that included the novelist Neil M Gunn and the poet Hugh MacDiarmid, Shepherd enthuses about contemporaries such as Virginia Woolf, to whom she was compared. This literary passion, along with an unconventional private life, is at the heart of a play that swirls around her story, taking us from wide-eyed child, discovering the beauty of pine cones, to care-home resident, refusing to be patronised by the staff.

Coyle switches from excitable youth to stiff-limbed old woman and all points in between, while Adam Buksh gamely plays lovers, academics and carers. If the play skims the surface of Shepherd’s appeal as a writer, it is nonetheless a warm-hearted evocation of a life led with self-determination in and out of the shadows.

• At Pitlochry Festival theatre until 14 June