As my fiftieth birthday loomed, I had a vague sense of getting out of the woods before the trees arrive. But I couldn’t face a party. Too demoralized. Fifty marks the stage another writer recently called, ‘the retreat from Moscow’. What’s to celebrate?

But I had to do something. The dreaded day fell at the end of a US book tour which left me beached in San Francisco. So I blackmailed a friend from the east coast, he flew over, and we took a road trip up the fabled Highway One, the 660-mile über-route that shadows the Pacific from the affluent canyons of Orange County to the arcadian grasslands of the Mendocino Coast. Actually, we only did the much lonelier northern half. We passed two cars one day. The drivers waved.

Here one sees the seismic nature of the Californian landscape: rolls and rolls of once liquid rock - and my map revealed that one particular region of the highway is actually called the San Andreas Fault Zone. Offshore, central-casting Californian surf performed for a hundred miles without a single tousle-headed surfer – the water is too cold, and the current too powerful. Besides, the northern Californian Pacific is uniquely studded with a particular kind of pinnacled rocky extrusion a hundred feet or two offshore – breakers for the breakers. Inland, cattle and sheep spread themselves over the northern chaparral.

Snuggled in the lee of the coastal cordillera, Highway One is too far from anywhere to attract settlers in significant numbers. A few farmers slug it out, cultivating land watered by the rivers that pour off the coastal ranges. The loggers have long gone, their lumber railways colonised by black oystercatchers. This is California as it always was, without the imprint of the Spaniard, the whaler, the gold digger, the technocrat - the landscape that launched the California dream.

We had a great time – among the best. On the day itself we stayed in a tiny converted boat on a ranch at Howard Creek north of Westport. There was nowhere to eat, so we bought a picnic of Alaskan salmon and local blueberries at the Westport General Store and ate it by candlelight in the boat. Perhaps fifty wasn’t going to be so bad. 

Access All Areas: Selected Writings 1990-2010 is published by Jonathan Cape.

Sara Wheeler was brought up in Bristol. She read Classics and Modern Languages at Oxford University before embarking on polar explorations. A traveller, journalist and broadcaster, she lives in London with her partner and two children. She is the author of six previous books, including Terra Incognita: Travels in Antarctica, Cherry: A Life of Apsley Cherry-Garrard,Too Close to the Sun: The Life and Times of Denys Finch Hatton and The Magnetic North.