Nursing torn tendons in my foot and hand, we're hiking 100 kilometres along California's volatile San Andreas Fault, climbing and descending more than 3500 metres, ever alert for rattlesnakes, ticks, poison oak, sheer cliffs, earthquakes, tsunamis and mountain lions. Why on earth are we having so much fun?
Because it's all about extremes, pain and gain – an exhausting slog replete with luxury, an opportunity for body and soul to dissolve into lavishly changing landscapes spiced with just a little terror.
In short, a faultless hike along a geological fault, oscillating wildly from the sublime to the ridiculous. My body, speaking American, will utter the occasional shriek: enough already!
Yet we plough on, enchanted by our 10-day, self-guided luxury Wine Country Trek from San Francisco into Marin and Sonoma counties. As we walk, hobble, limp, lurch and, on one occasion, headbutt the ground, the landscape turns like a kaleidoscope from dune scrub to coastal hills, oak woodlands, old-growth redwood forests, chaparral ridges, canyons, cliffs, estuaries, pastures and vineyards.
It all begins in San Francisco's trendy Argonaut Hotel. Wine Country Trekking's motto is "experience luxury on foot" and so far, so excellent. After exploring the city, riding the cable cars, scoffing Dungeness crab and Ghirardelli chocolates, we're gazing from our bed across the bay to Alcatraz, plundering our welcome pack, which includes a taste of things to come – a bottle of Sonoma Gloria Ferrer Blanc de Noirs methode champenoise.
Supine, it's a breeze reading the personalised trail guide that includes maps, detailed hiking trail notes, meals and accommodation. Nineteen-kilometre days with 640-metre climbs? No worries.
Potential hazards like those mountain lions are dealt with thus: Appear as large as possible – we're working on it. Tonight, it's wild salmon and succotash at nearby Scoma's as the night turns dark blue and a giant supermoon augurs well for our first day's walk.
We have in mind Mark Twain's musing that "the coldest winter I ever saw was the summer I spent in San Francisco" but it's a sunny 14-kilometre, fairly flat walk today along the bay, through the restored coastal habitat of San Francisco's Crissy Field. Before we cross the Golden Gate Bridge, we collect avocado and aioli ciabatta rolls from the historic Warming Hut Cafe. A lovely breeze propels us across the sculptural red limbs where "seismic retrofits" are in progress. It's a sharp reminder that we walk a fault line that shifted so dramatically in the 1906 earthquake, the land leapt six metres in a minute.
We're en route to the French Riviera-like village of Sausalito, in Marin County, named for its little willows or "saucelitos". Casa Madrona's four-poster bed and balcony offer wide bay and yacht basin views.
We eschew the spa, wallowing instead in our own spa bath before our fine meal at Poggio's – Alaska panfried halibut with baby vegetables sent on its way with Napa's Domaine Carneros by Tattinger.
Poggio's also offers an excellent breakfast of porridge with berries and cappuccinos that we consume watching men collecting takeaways with poodles in their Porsches. Our picnic is from Venice Deli – the salami-and-cheese-stuffed Italian Special for me (those mountain lions, remember?).
Today's hike is the same distance as yesterday but soon I'll be lauding my friend, the walking pole, during our 700-metre gain and loss. The two-kilometre steep slog between Sausalito's exclusive homes merely brings us to the beginning of our climb through oak and chaparral into the coastal ranges. There will be all-day vistas of the Pacific to our left and Marin and San Francisco Bay on our right as we follow the trail to the Oregon border 770 kilometres away.
California's state rock, serpentinite – greenish and scaly – will mean I also fall often on my backside. A snake slithers over my foot on a rest break (the absence of a rattle comforting) and I foolishly touch poison oak to see if it's poison oak (it is).
Red-tailed hawks, ospreys and bottlenose dolphins accompany our serpentine hike. Soon migrating whales will join them. The sun is slipping as we descend finally into Muir Beach, crossing Redwood Creek that will, in winter, welcome spawning steelhead trout and coho salmon.
Our hydration packs are drained as across a willow meadow we spot our night home – the 16th-century Pelican Inn set in cottage gardens of lavender and tibouchina. Its English owner transported it piecemeal across the seas. There's even a "snug", but the fare is far from Elizabethan.
This is our first taste of Marin's locavore obsession – even Prince Charles visited Marin in 2006 to study organic farming methods. Tonight, it's beet and watercress salad with goat's cheese and crisp walnuts, followed by seared organic ribeye with fingerling potatoes and asparagus.
We will learn later that some people – "mostly Americans" – abandon the hike after this day and ask to be "taken to the nearest mall". Silly them. The thing is, there aren't too many malls in Marin and no billboards. Locals guard against crass development, so places like Muir Beach only an hour from the city are lightly populated paradises, as are towns like Bolinas and Stinson Beach.
Conservationist John Muir said, "The mountains are calling and I must go." So must we. An English breakfast heralds today's 14-kilometre hike steeped in scents of bay laurel and sage. The vertical climb out of Muir Beach launches us up "the sleeping lady", Mount Tamalpais, Marin's highest landmark revered by the Coast Miwok Indians.
Lunch (shared with a discarded Wallabies beanie) is on top of the world with San Francisco and Pacific vistas, before we plunge into the russet natural cathedral of Muir Woods, one of the last old-growth coastal redwood forests (and Rise of the Planet of the Apes location, just so you know). We float down through the peace of these "God's first temples" that stood when Rome fell.
On the canyon floor, redwood sorrel and sword ferns alternate with delicate redwood violets but the ancient trees are king. Eventually we must face facts – a sharp descent means thousands of rough stairs back up to Mountain Home Inn at Mount Tamalpais' Mill Valley, which writer Jack London called "America's little Switzerland".
It's a Bavarian-style hiking lodge perched among clouds. How amazing it is to sink into a fragrant spa while the sky reddens and the bay lights twinkle on.
We wake sore and gird ourselves for our 15-kilometre hike across the Point Reyes Peninsula to Olema – the Miwoks' "lake of little coyotes". Today we enter "cow heaven". Salt air, cooling fogs and verdant pasture ensure artisanal cheeses that justify Marin and Sonoma's designation as "the Normandy of Northern California".
A driver delivers us to Limantour Beach on Drakes Bay, so named for Elizabethan explorer Sir Francis Drake. Avoiding "sneaker waves", for this Pacific coast can be fierce, and admiring the white cliffs that reminded Drake of Dover, it's tempting to stay on this deserted shore with its glassy sea and crab-harassing California gulls.
But up we go towards Mount Wittenberg through a forest tapestry of Douglas fir, western hemlock, aspen, oak and Monterey cypress. As always, we are the sole hikers, apart from one runner who squeals, "Other humans!".
Off the mountain at last and only a short way from Olema, I truly understand the term "becoming one with the landscape" when I slip, ripping tendons and cracking my skull. My first grateful yet craven thought is that I can avoid tomorrow's "challenging" 19-kilometre ascent of two mountains. My husband's weird grin tells me he's of a mind. We've also just spotted a mountain lion warning.
Another lovely lodge awaits – the Audubon suite at Point Reyes Seashore Lodge with its Adirondack chairs scattered through lavish gardens. Tonight we eat at Sir and Star, enjoying lyrically named dishes. Everything is West Marin-grown, except "life's essential champagne" which I must have of course, for the pain.
The following day, we sleep in blissfully, before going by Marin Stagecoach to the Dancing Coyote Beach Cottages at Inverness on Tamales Bay. Here, Mary-Ellen, our private caterer, cooks our dinner (telling us we aren't the first to avoid the "challenging" day). Stuffed with Point Reyes cheeses, grilled ribeye, ratatouille, garlic mash, heirloom tomatoes from her garden and homemade apple pie, washed down by a luscious Chateau St Jean Sonoma 2008 cabernet sauvignon, we drift off with the stars glittering through the skylight.
My injuries mean we miss the planned Tomales Bay kayak but, eh. Our fridge is packed with food, neighbouring Saltwater serves plump local oysters and good coffee, and nearby Point Reyes Station is a Byron Bay-esque village with farmer's market, gourmet food and wonderful bookshop.
Sonoma, that "Valley of the Moon" and apotheosis of our hike, is our final destination. We walk the Jack London State Historic Park to explore his experimental farm and the redwood trails to the 1600-year-old "grandmother tree" (trying to ignore the "caution: rattlesnake in area" and mountain lion signs).
Then our two-night winery extravaganza begins with a private tour and tasting at Benziger's biodynamic winery. Tonight it's the Michelin-recommended Gaige House Inn in the Sonoma hamlet of Glen Ellen, treated with a luxurious suite, wine and cheese evenings, the terrific fig cafe and Glen Ellen Village Market nearby.
Wine Country Trekking's Sheila, Mary and Greg, who spotted a gap in the US market for European-style hikes, have fine-tuned this trek, adding personal touches. Mary kindly drives us between wineries on our last day, meaning more time for our private tastings at Hamel, B.R. Cohn and Ahh wineries.
The delicious sparkling syrah and pinot noirs (that fickle grape made famous in the Sonoma-located film Sideways) from Ahh winemaker Bruce Rector are a fine way to end our journey.
Alison Stewart travelled with assistance from Wine Country Trekking and some providers.
Qantas begins direct flights from Sydney, Melbourne and Brisbane to San Francisco in December. See qantas.com.au
San Francisco to the Wine Country 10-day/9-night self-guided hike includes trail guides, premier lodging, in-hike transfers, breakfasts, lunches, private wine tastings, kayaking, private catered dinner. From US$2650 ($3718) a person sharing. Shorter options available. See winecountrytrekking.com/
Alison Stewart travelled with assistance from Wine Country Trekking and some providers
FIVE MORE US HIKES
BRYCE CANYON AND ZION NATIONAL PARKS, UTAH
A six-day/seven-night guided hike through amphitheatres of rock formations and pink hoodoos (pinnacles) to explore hanging plateaux, waterfalls, red rock walls and narrow slot canyons. From US$1455 a person, June to September. See pure-adventures.com/
HUDSON RIVER VALLEY, NEW YORK STATE
A relatively easy guided seven-day/six-night hike along the picturesque New York River, walking historic trails and visiting legendary sites. From US$2295 a person, May and October. See wonderwalks.com
ROGUE RIVER, OREGON
Hike one of America's great historical trails originally built for pack mules supplying miners in the Rogue River Canyon. This four-day, self-guided, supported hike has historic lodge stays. Downhill most of the way. From US$1149 a person, May, June, September, October. See wildrogue.com/
LAKE CLARK NATIONAL PARK, ALASKA
A challenging guided eight-day/seven-night hike into an alpine paradise of salmon streams, turquoise glacial lakes and prime grizzly sightings. US$3550 a person, August. Easier options available. See trekalaska.com/
ACADIA NATIONAL PARK, MAINE
Acadia is one of Maine's best places for walking. It's criss-crossed by more than 160 kilometres of historic trails and carriage roads built by philanthropist John D. Rockefeller Jr in the early 1900s to avoid the use of cars. This small-group, guided, easy six-day walk (three to 12 kilometres daily) offers premium accommodation and costs US$2998 a person. See countrywalkers.com/