The neglect I had shown to my native Wales over the years, while writing about the streets of Delhi, or small town life in Kansas, shamefully hit home recently while listening to music in my apartment in Hong Kong, where I have been living for much of the past 20 years. The voice of the great British singer-songwriter Ian McNabb rang out loudly: “I never saw my hometown ’til I went around the world.”

These thoughts on a day of unbearable humidity and oppressive Hong Kong heat gave the germination of the idea behind my book The Long Unwinding Road. I grew up in the south, the commercial and industrial heartland of Wales that was completely divorced, I considered, from the big green north, where people were more tied to the land, and nature had done some of her best work.

So, in the autumn of 2022, I put Asia behind me and headed back to travel the length of the country to find what I’d been missing, or more accurately, what I’d forgotten.

To do so I borrowed a battered old mustard-tinted Vespa named Gwendoline from Clem, a major force in the south Wales mod movement, and set a course to traverse the nation from Cardiff, the glass and chrome capital in the south, all the way to Llandudno, the Victorian resort on the northern coast.

There is only one road that runs the whole way, the A470. But it’s one road in name only. Its length is made up of the remnants of many other routes stitched together like a Frankenstein’s monster of a road. Some are dual carriageways – smooth, elegant, and straight – but others, especially in the green middle of the country, are as wide as only one car, lined by hedges and watched over by uninterested sheep.

The journey started on a rugby international day in Cardiff, all dragon flags and daffodil hats. This is when the city wears its Welshness like stage makeup. The uniform red jerseys of the crowd massing in St Mary Street are the rouge on the city’s cheeks. Here the Welsh are one in song, outside the pubs and along the packed pavements. They edge slowly, closer to the cathedral of the game, the Principality Stadium, sat like a fat spider, with its legs angled ready to pounce on the silent and still Cardiff Castle next door. At the heart of the city centre, the high castle walls and tower bring a much-needed sense of heritage to a city that flirts wildly with the contemporary. Cardiff can seem hellbent on homogeneity, and yet on these days, when the world is watching, it puts its best Welsh face on and thrives in the attention.

The Rhondda Valley to the north of the capital is still recovering from both the scars of industrialisation and the emptiness of industry’s departure, but you won’t detect this in the people of Pontypridd who bustle through the town. In mid-afternoon I sat alongside Maggie and Jean in The Prince’s cafe on Taff Street, one of those fabulous centres of local life that dot the Rhondda and where the crucial news is passed from table to table. The waiting team, in their faux Lyons Corner House black, were balletic around busy tables and placed proudly in front of me the local favourite corned beef wedge with a rich brown gravy that glosses on the spoon. It was as fabulous then as it was when my grandparents would have treated themselves to it in these same seats decades ago.

Leaving the Rhondda is like stepping through the back of a wardrobe. Behind is the grey, scarred land of industry, while ahead lies the beauty of mid-Wales. There are more shades of green here than in Tom Jones’s paean to the grasses of home, and hills that defy logic: locking here, rolling there, smooth-sloped or scree-covered. Gwendoline the Vespa struggled on the road that winds through them, and I was too distracted by the landscape, which appeared to be straight from a Kyffin Williams canvas, to pick up the whine from her engine that suggested more trouble was to come.

This is the land beneath the wings of the red kite, considered Wales’s national bird. From a lonely pair some three decades ago in Rhayader, the skies of Powys now are loaded with this most glamorous of predators. Does any bird hold its position in the bright blue mid-Wales skies more proudly than the kite? Pulling over to the side of the road, partly to end the scooter’s complaints, I put my hand up to shade my eyes from the late sun and caught the silhouette of a bird. Circling around me, I could see its wavering tail and tilting wings, and then its dive was a thing of beauty, arrowing straight, skimming the ground with barely a touch, then on and up, to complete an arc that was as sweet as any rainbow.

By the time I’d reached the north at Mallwyd, I could sense the change in the land and the air. Rolling hills were now jagged mountains that in some places loomed so high over the road on the approach to Dolgellau that you’d think you were riding through a tunnel. The air felt colder, the wind whipped harder. A sharp bend near Blaenau Ffestiniog allowed a glimpse of Cwmorthin, a lake of the deepest sapphire, then another blind twist in the road and I was climbing steeply on Snowdonia’s roads just inches away from sheer drops that seemed to have no end.

Gwendoline eased into the downhills after the straining climbs, and the air against my face, exposed to the elements on these slopes, was thrilling. Every heart-stopping rise and fall on this road through Wales revealed something that made me blink in wonder: the glistening River Conwy crashing over rocks and running clearer and fresher than any river I’ve seen before; the road-covering canopy of trees that ended abruptly at the view over the estuary at Conwy, as startling as it was dramatic. And all the time, the imposing backdrop of the Snowdonia ranges, cradling and nudging the traveller to journey’s end at the ocean. This is the Wales that people who haven’t been here expect: magical and majestic, an almost fantastical place.

In fact, for a few blissful moments, at the end of the ride through the nation, this small corner of the world seemed utopian. Looking out at the sea from the pebbled beach at Llandudno, sat for the last time on the Vespa’s bench seat, I struggled to think of anywhere else I could find such a moment of peace. In the three days of the journey, I had been left astonished by the variety that this small country, my home, can offer.

The travel writer HV Morton was here in 1931, but his words could have been written for me today: “I remembered lake, mountain and valley, riverbank and woodland, salt marshes and the high cliffs of the south where the big rollers pile in from the sea … Wales is a beautiful and romantic land …”

The A470 offers a variety of landscapes and nature, cities and hamlets, past and present, in a measure almost unrivalled by any other roadway in the UK, and is Wales’s most glorious long unwinding road.

The Long Unwinding Road by Marc P Jones is published by Calon (£18.99). To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply