Porlock Hill (aka the A39) is torture. It's a breathtaking one-in-four gradient that zigzags up from the Bristol Channel coast to the crown of Exmoor, and is one of the steepest A roads in Britain. The adjacent Porlock Toll Road (porlock.co.uk/about/tollroad.php) is one of the longest: a breathtaking five-mile climb with Alpine-like hairpins and dizzying views of the sea from high wooded cliffs. Cars struggle to the top, even in a low gear, but cyclist Chris Green loves the challenges of his native Exmoor.

He's not alone. Porlock Toll Road is one of the classic climbs on the Tour of Wessex: the world-class cyclosportive that sprints around the West Country for three days in May.

It's not just the challenging gradients that attracts cyclists, says Chris. "The roads are often empty and the scenery is stunning; it's one of the few places in the country that still feels like a wilderness."

With one foot in Devon, and the other in Somerset, Exmoor national park's attractions include wild ponies, red deer, birds of prey and glittering night skies (the lack of light pollution made it Europe's first Dark Skies Reserve). On the coast below, in the spectacular Valley of the Rocks – between Lynmouth and Martinhoe – Chris has cycled on clifftop roads where you can spot goats with "horns as big as your arm".

He enjoys the "brutal" route home from his bike shop in Braunton to Simonsbath – a village high on Exmoor – the last leg of which takes him uphill from Lynmouth via Watersmeet. But if you don't like steep hills, there are much gentler routes in the valleys around Dulverton and Exford, to the southern edge of the moors, he adds. "The whole area is ultra picturesque."

• What to see: Tour of Wessex (pendragonsports.com/tour-of-wessex-2013), 25-27 May.

More information at visit-exmoor.co.uk