Miller's Dale to Edale. 11 miles. Miles to date: 525.9.

It has been a day of two halves.

For the first, Reb, Max and I took it as easy as we did on the rest day before. Too many cups of tea and pieces of cake while trying to avoid the midday sun. Wearing boots was forbidden. It was flip flops or bare feet. It was the first time I've properly relaxed this whole trip and it was bliss.

Then, after a picnic on a grassy bank above Miller's Dale – lanes bursting at their slim seams with cyclists, biker-streams and cars – we said goodbye. Reb and Max took the path south, and I pulled on the pack and started the long, slow climb north.

For the second day I was using a mix of the Pennine Bridleway and Limestone Way. After so much disappointment using other long-distance trails, both get full marks. They're well signposted and firm underfoot, often making use of quiet farm tracks. Hats off to the local councils and National Park: they've transformed miles of what could be uneventful farmland into fine walking country.

The afternoon started with farm tracks leading up to the hamlet of Wheston. In hindsight the route I chose seems bizarre. There looks to be a far more interesting alternative only a few hundred feet west using Monk's Dale, Peter Dale, Hay Dale and Dam Dale. Next time... ;-)

You get two choices when crossing Derbyshire. Stick to the dales, or reach for the high ground. Both have their benefits, with the latter offering big-sky panoramas.

I can't say enough good things about walking these paths. The waymarking is superb.

Walls and barns.

Easy walking, sure, but hot.

And while there was breeze enough on the tops, my eyes were always on the next oak copse or blackthorn hedge for even a moment's shade from the relentless overhead sun.

By and large I've been blessed during my journey with good summer walking weather. Which is to say overcast skies with sunny spells and enough of a wind. Yes, I've had a couple of washouts, and Cornwall felt like one long day of perfect blue skies. But today was my first day of challengingly hot weather.

It was fine, but it slowed everything down, each step demanding that much more effort, more breaks for more water, heat haze above cracked farmyard mud.

It wasn't just me. Sheep sheltered in wall shadows, cows flopped among buttercups, even the sparrowhawk was swooping without commitment.

Yet still the farmers worked on, big teams in the pocketed hay meadows, reaping while the sun sone. They were doing the same in Cornwall three weeks back. I've followed the summer north.

The trail also used a number of quiet backlanes passing secluded farms.

Gathering the hay.

Relief only came when I dropped down to Castleton, the little tourist hotspot sandwiched by the White and Dark Peak. Down in Cave Dale the temperature felt 10 degrees cooler, yawning cliffsides throwing shadows over depths that never see sun.

It was a busy spot, couples sunbathing, kids clambering on limestone turrets, parents eyeing the man-made ruins of Peveril Castle above. It never saw battle. Nor was it heavily garrisoned. At one point it was home to just a porter and two watchman. Now it's the realm of ravens and crows.

Then a break in Castleton itself. Passing the ice cream queues – and the many signs saying SOLD OUT OF ICES. MORE MONDAY. Instead, a pint of lemonade in the Bulls Head with its striking view of Mam Tor.

It was 4 o'clock and if anything even hotter than midday. Five miles down. Seven to go. I tried not to think too much about what lay ahead and busied myself instead by hydrating.

Looking down into Cave Dale. Peveril Castle is in shadow on the escarpment.

Castleton village green.

Bulls Head pub, Mam Tor behind.

If you walk Castleton's streets your eyes are pulled up by mighty Mam Tor.

They call it The Shivering Mountain in these parts for the ceaseless shudders of shale that dominate its southeastern flank. For years man tried to tame the mountain with the once-busy A625 crossing. In 1979 the highways agency gave up for good, the ripped and buckled road a testament to the unceasing movement of the crumbling hill that is slowly falling apart.

At 1,696ft Mam Tor is a respectable height, but in the heat it felt three times higher. I was meant to climb it en route to Edale but when I looked again at the maps it seemed like the kind of LeJog route flourish that could easily be avoided; a nice idea in good walking weather, not today's sweatfest.

So I cut the corner by crossing the long shoulder at Hollins Cross. It's still a great viewpoint, with panoramas of the route behind: Castleton and the Hope Valley, ahead quiet Edale and the rising Dark Peak wall that I will tackle tomorrow.

Mam Tor – the mother mountain – and Little Mam Tor below.

Remains of the abandoned A625 road that once linked Sheffield with Chapel-en-le-Frith.

The Hope Valley, Castleton in the centre, cement works to the left.

The view north: the Black Peak, cloaked in shadow, and the Vale of Edale.

Shifting light on Mam Tor.

The walk through Edale is pure loveliness. You know you're in walking territory when one of the valley's two pubs is called The Rambler. It's too remote for the car tourists and bikers, the mountains that crown the valley making road assaults hard work. Here it's stone walls, sheep farms and old broadleaf copses above the busy River Noe, channeling water from the peat bogs of Kinder that never dry out.

I push on in the evening heat, under the railway and up the increasingly steep flanks of Kinder Scout, meeting an old terrace path lined with wind-bent hawthorns that leads to my resting place for the night.

It's another fantastic YHA, tucked into the hillside in a wooded glen. From my window I can lie in bed and look at the limestone crags of Back Tor turning pink as the sun finally loses its bite. There's veggie curry for dinner and old-school cake and custard before you give your plate to potwash. There's also stable wi-fi, a big room and a bar.

I'm a youth hostel convert this trip. They've kept the good stuff from the old days and bought it up-to-date where needed. For £35 a night it's impossible to complain.

When I arrive the receptionist is busy with schoolkids. They've ordered a whole load of specialist coffees for their teachers and you get the feeling the receptionist is no coffee drinker. This is an activity YHA that's year-round busy with parties who stay on-site for archery, rope courses, orienteering, and go off for rock climbing and watersports. It gives the hostel a boisterous, frenetic energy which is welcome right now. I've been lucky to stay with and see a string of friends and relatives over the past two weeks. But I'm on my own now as I head north. Busy is good.

Please close the gate.

Back Tor and Lose Hill – continuation of the Mam Tor ridge.

Back Tor and Lose Hill.

Jacobs lamb.

Edale YHA.

So it is that I finally reach the Pennine Way, the long distance footpath that will take me 267 miles along the north of England's high ground spine and deliver me into Scotland.

It's a trail of superlatives. The first official long distance footpath in Britain, brainchild and memorial to rambler Tom Stephenson, who was inspired by walks like America's Appalachian Trail. It visits England's highest waterfall, highest market town and – more importantly – highest pub. It's the best known path in Britain. And though it's not quite the longest trail (that honour goes to the South West Coast Path), it is widely considered the toughest of them all.

In the shadow of Kinder Scout I can't help but feel a gnawing sense of trepidation. Excitement, yes. But disquiet too. The first two days are legendary for breaking ambition. And while the peat bogs that walkers once struggled through are now paved with limestone flags – making routefinding and passage easier – plenty of walkers' long distance dreams fade on day one.

It doesn't help that the forecast is as today: 25 degree heat and no let-up in the sun. No shelter either on the bleak, featureless moor.

For comfort reading I turn to the only guidebook author I have ever trusted, Alfred Wainwright, and his Pennine Way Companion.

"This is a tough, bruising walk and the compensations are few," he notes. You don't do it for fun, he continues, but "to get it off your conscience".

Hmm.

His description of Day 1 isn't a confidence builder either. If weather is poor, consider delaying your start across the grim territory ahead, he advises. "Better a postponement than a postmortem."

On that cheery note, I settle into bed for a night of ominous dreams as the stream that flows past the hostel keeps trying, and failing, to empty the vast boglands above.

Evening light on Mam Tor.

Next: Day 36 – Edale to Crowden (Old House).

Previous: Day 33 – Thorpe to Miller's Dale.