Leaving the Oaxaca coastline, which is in no ways flat, for the real mountains, lost within their beguiling, silhouetted layers of blues and greys.

In the shelter of a bus stop – sanctuary from the beating sun – I met Melcuidades, a roving musician hitching a ride to a nearby beach. ‘What kind of music do you play?’ I asked. 'Music for women to fall in love to,’ he replied. And with that, he pulled out his plectrum, and sang about the workers in the fields, the pounding Pacific, the birds that soar above the waves, the magnitude of the mountains, and God.

‘Tis the season of mangos. These sweet, succulent fruit (in my Top Three Fruits of All Time) are sold by the roadside, from makeshift palapas or straight out of the backs of old, rusty pickups. Generally divided up into buckets or crates, the old lady vendor I stopped at just gave me a handful and wished me well on my journey.

Another hot and sweaty self portrait. On this occasion I mistimed my day, and between two hilly headlands, ran out of food and water. I was really suffering, limping along a few kilometres at a time, running on empty. Finally I chanced apon a group of girls selling ready-peeled oranges and coconuts by a speedhump in the road. I was a good customer…

Once I cut inland, there were more tempting eateries on offer, like this bustling market in Juchuatan. There, a platter of 'sopes' - open-top tortillas loaded with beans and melted cheese - cost little more than a dollar. The colourful, Mad Max-style Motocarros added ambiance too.

Windfarms - a sight that can strike dread into a cyclist's soul. La Ventosa's reputation preceded it, a tract of exposed land home to furious winds, whose gusts are strong enough to blow trucks right over. Luckily, by April the winds have dropped. Unfortunately, this wind is replaced by an intense heat, as April is also one of the hottest months in Mexico.

Not much in the way of shade either… At any roadside store I came across, I gulped down as much as I could drink. I was beyond caring what it was, as long as it was cold... On this stretch of the road, I also caught up with Romain, a Frenchman riding down from Montreal, on the road for 10 months and headed south to Argentina.

As we crossed the bridge at Ostuta, we spotted an enticing river in which to take a much needed soak. The place was in full swing, packed with Mexicans eeking out the last day of the rowdy Semana Santa festival. Gathered around plastic tables, they listened to well-dressed, uniformed Mariachis blast out tunes as they chomped on platters of garlic-roasted prawns, washed down with generously large bottles of beer. Mexicans like to start their drunken revelerie early, so by the time night had fallen, everyone had run out of steam and headed home - making it a perfect spot to pitch our tents.

The next morning, as we were breakfasting on a platter of quesadillas in Tapanatepec, two Japanese riders passed by. Incredibly, I'd already met one of them in Alaska at the very beginning of my trip, some 9 months ago. Even back then, Koko had already been on the road for over three years…

The Japanese had a photo of the route profile for the next few days. The big lump is the climb from Tuxla to San Christobal de las Casas, which transports you from a lowly 500m to a lofty 2300m in 46 straight kilometres.

I've been running locally bought slick tyres for this road section of the journey. But just as we were passing a military checkpoint on the outskirts of Tapanatepec, my rear tyre blew out. So I nipped back into town, and picked up a tractor-like local offering for $8. The advantages of travelling with 26'' wheels.

The climb begins. Not a puff of wind. I don’t think I’ve suffered this much for a long time. Another day that touched 50 degrees...

If it’s biblical, does it count as graffiti? Had I been more familiar with the Bible, I might have been distracted from my toils and spent some time pondering its message: For God does speak – now one way, now another – though man may not perceive it.

25 kilometres later, at Rizo de Oro, I took a much needed break. Romain had called it a day, as he was suffering from a bad stomach and dehydration, so I rode on alone.

Sustenance. Just what I needed to fuel my empty legs.

Later that day, I caught up with the Japanese. In the height of a Mexican summer, water carrying is key. Yutaka had a custom mount for this massive water container.

And just in case, he also had a good four and a half litres of liquids at the back…

We rode together for the next couple of days, towards Tuxla. The ride involved a good deal of highway miles, and on the whole, was pretty dull. Highways certainly get you to your destination quickly, but there's little chance to interact with anyone along the way. A good reminder why following a swathe of tarmac and jostling with fast traffic doesn't do much for unravelling the mysteries of Mexico.

Reaching the Zocalo, San Christobal. I left at 6am to beat the heat, and topped out in the cooling pine forests of Chiapas by 11am. I was in a hurry as my teeth had started to kill me. Time for a trip to the dentist, I think. The first in 12 years. Yikes…

San Cristobal is an incredible place, and deserves a blog post of its own - a colonial town set amongst the mountains and pine forests, home to Zapatista sympathisers, indigenous Indians, international musicans and artists, travellers from around the world, and colourful VW Beetles. And a good place to take a rest…