Red Saab, yellow field, blue sky, camera. Neil Roland wasn't really asking a lot to capture the essence of southern Sweden

"Yes, but it isn't possible. Come back in three weeks. Go away, please. Welcome!" Being politely embraced and rebutted with the same smile can be something of a Swedish trait, and I wasn't surprised by the response, standing in the tourist office in Trollhattan, a small town 50 miles north-east of Gothenburg and home to the excellent Saab Museum.

"Yes, but it isn't possible. Come back in three weeks. Go away, please. Welcome!" Being politely embraced and rebutted with the same smile can be something of a Swedish trait, and I wasn't surprised by the response, standing in the tourist office in Trollhattan, a small town 50 miles north-east of Gothenburg and home to the excellent Saab Museum.

Had I asked about the cost of taking a steamer on a jaunt down the Gota Canal, I would doubtless have been told all I wanted to know. But what I was after was an classic old Saab car, ideally scarlet, to take into the glorious southern Swedish countryside where I would photograph it against a yellow backdrop of rape fields and, if my luck was in, beneath a cobalt-blue sky.

I wasn't being deliberately difficult. The idea was to provide a striking front cover for The Rough Guide to Sweden which I was co-authoring. The three primary colours seemed perfect for presenting an essence of southern Sweden, particularly the summer sun-drenched province of Skane, with its Mondrian patchwork of rape and poppy fields studded with black windmills.

Having spent four months hiking, cycling, driving and rowing through the idyllic countryside of this exhilarating kingdom, I had become pretty familiar with that national monument, the Swedish tourist-office assistant. Mostly called Karina, Christina or Inga, they are found smiling all over the country, from mountain villages in the north to medieval chocolate-box hamlets in the south. They have been my saviours, my heroines, and, on occasion, have reduced me to near-asthma attacks of frustration. They are, I believe, all made in a factory deep in the forests of Smaland and are programmed to lose any sense of urgency at first detection that one is in a hurry, and to be informative without yielding the information needed.

Well, a classic old Saab seemed off the menu. The fact that returning in three weeks when the director would be back was not practical for me was received with another warm, apologetic but equally determined smile. I left.

In the hazy heat of this Midsummer's Eve, I decided to head east along Route 44, skirting the southern tip of Lake Vanern to Kinnekulle, the Flowering Mountain which stretches east from the town of Lidkoping. The mountain itself surges up through a glorious undergrowth of wild flowers and lush greenery. It is topped with a strangely flat summit of hard, volcanic rock which 400 million years of Swedish winters have failed to wear down. Beneath are paths, ancient sites and tiny communities which, though very much on the mainland, maintain a certain insularity.

The Midsummer solstice could not be more pagan, the gardens of every cottage erecting a huge wreathed phallus around which friends and family dance in circles thanking whoever they thank for fertility and virility.

It seemed appropriate, on this most important day in the Swedish calendar, to stop at Husaby church. I had visited it three years previously and been mesmerised by this millennium-old church where, in 1008, the English missionary St Sigfrid baptised Olof Skotkonung, the first Swedish king to reject Viking gods. What had struck me then was that there was no security at all. I had entered the unlocked, silent little church alone, and all that stood between me and stuffing the ancient font in the back of my hatchback was my own moral code.

As I entered this time, the church was full, presumably because of the festivities. Everyone was in medieval garb. I settled into an empty front-row pew between a woman in a violet, cornet-shaped headpiece and a man in viridian breeches. They stared at me, but Swedes sometimes do that. Perhaps they felt my cut-off denim shorts were a bit too cut-off for such a church. Only when a 6ft 8in Viking, swathed in a sage cloak, asked if I was with the bride or groom did I realise why I was the most underdressed.

Outside, a few hundred yards down a shady track with just silence and butterflies filling the air, I found Lasse's Grotto. Sunk into the rock and camouflaged by ancient oaks, this two-room cave is where a local eccentric, Lars Eriksson, and his wife lived for 31 years until his death in 1910. Rare photographs show his cosy, bizarre interior, and I sit and contemplate for a moment in this time-forgotten hideaway.

Following the road north towards the mountain itself affords the sort of sights only possible when a country has considerable private wealth of the very old and unostentatious kind. Stately manor houses sit like forgotten old duchesses at the end of long horse-chestnut avenues. A couple are hotels, like the 14th-century Honsater Slott near Hallakis, the only settlement of any size around here. With its Naples-yellow façade, it is a mellow spot to savour the freshest Arctic char.

Nearby, Hallekis castle, still home to the Counts of Hallekis, boasts gardens devised by the British designer Simon Irvine, while others, such as Rabacks, with its striped awnings and honeysuckle, stand empty while their millionaire owners cramp themselves in apartments in more southern capitals. Each mansion has its own railway station named after it, and six little trains chug along the route daily, hardly disturbing the poppies growing between the tiny tracks.

"Hey!" shouts a woman's voice. I look down into a large garden, where men and women are laughing and kissing around a cloth-covered trestle-table (schnapps acts like paint-stripper on Swedish reserve). The woman has a trickle of stars painted down her face. She invites me to join them for herring marinated in rum, new potatoes and then blueberry tart, sour cream poured on everything. This is Midsummer, a time to share. I do. She turns out to be Therese Johansson, Sweden's only full-time woman blacksmith. "Dance with me around - how do you say it - our giant penis," she offers. Who could refuse.

I see it that night, as I return to my hotel. Parked outside a small, yellow-painted wooden house. A bright scarlet 1961 Volvo P1800. A vintage Saab's age-old rival. I knock at the door and a woman in a dressing-gown answers. She speaks almost no English. Yes, it is her car. Yes, I can photograph it. Tomorrow. When she gets up. What time is that? Four o'clock. What? "I am hospital," she explains. "While I still alive, I like see all the sun."

The next morning, at four o'clock, I return. "We find your yellow field!" she smiles, throwing me the keys. "You drive," she says, answering a teenage prayer of mine. We speed on until we reach the twin 500 million-year-old plateaux of Hunneberg and Halleberg. We drive into a field of brilliant yellow rape. I take photographs and we share our only easy communication, singing a string of Abba hits.

In the end Rough Guides decided a river in the north was less contentious for its cover, but I had made a new friend who, I'm delighted to say, is still seeing the sun rise every day.