The wild and wacky sights along the Californian coast are best seen from behind the wheel of a convertible Mustang, says Mark C O'Flaherty

California might be geologically unstable and frequently ablaze, but you can't fault the weather. In LA, convertible sports cars are de rigueur, and business is done by bellowing non-stop into a Blackberry, poolside. I'm mid-road trip in a convertible gold Mustang that I've rented to "do the coast" from San Francisco to Palm Springs: 500 miles and 12 days of dazzling American highlights refracted through the lens of chrome, gas stations and the Go-Go's greatest hits.

Indoors and outdoors blur in a perpetually sunny California. The landscape is one long, hypnotic, six-lane acid trip from the retro-futurist 1950s Jetsons carwashes at the side of the road to muscle-bound dwarves in denim hot pants on the sidewalks of West Hollywood. It's a drive-by education in hyper-reality; the further you drive, you deeper and deeper you go down the rabbit hole.

I've learnt a few things about travelling with the top down, like the importance of reapplying sunblock to avoid big, white, inverse-Panda eyes after a day in oversized Dior Homme sunglasses. "It's a bit late for that buddy," chips a shopper in a Beverly Hills drug store as I perused the factor-80 Aveeno range, face aglow.

It's not all been blue skies and sunburn. In San Francisco the Golden Gate Bridge was shrouded in sea mist when I drove across, and I shivered on my stroll from the warm boutique comfort blanket of the city's W Hotel to dinner at Foreign Cinema. At first I sat al fresco in the courtyard, where classic movies flicker on a huge white wall, but was driven inside by Dante-powered patio heaters. Too cold, too hot... As Mark Twain is often quoted as saying, "The coldest winter I ever spent was a summer in San Francisco."

There's something British, or specifically Brighton, about San Francisco: the hills, the left-field politics, the desire for a good time in the face of drizzle, and the breezy gay bars.

The drive south, through Big Sur, is one long winding vertiginous wow, the coastal road undulating like a big dipper above and often through the clouds, the Santa Lucia Mountains rising suddenly out of the crashing waves below. This is Kerouac country, where the Beats came to escape the city and embrace the elements, and where Henry Miller lived, worked and had his ashes scattered. I make regular stops to snap the vista and to walk through the Goliath-like Redwood trees, only slightly unsettled by the signage promising infrequent mountain lion sightings and possible attacks.

Modern Big Sur dictates over $100 a night for a simple motel without a TV, while Old Big Sur is epitomised by the Esalen Institute, a centre for new-age life study – a throwback to the 60s, but now with added Wi-Fi and workshops on Leadership for Emergent Executives and Entrepreneurs.

At 1am every night, non-residents can come and bathe naked in the cliffside sulphuric hot springs. I've heard it's a must. Initially I have reservations at the lateness of the hour, and the nudity. But when I get to the hot tubs, the light is dim enough to preserve my modesty.

It's all very enchanting and liberating, but half an hour submerged gives you the general idea. Dutifully relaxed, and the experience box ticked, I drive back to the Post Ranch Inn – very much the New Big Sur – replete with five-star modernist tree houses and Hobbit huts. En route, I spot a young coyote going for a stroll through the thick, spooky, sea mist.

I drive on south, with a pause to take photographs of the malodorous elephant seals on the beach at Piedras Blancas (the stench is perhaps the most aggressively hyper-real encounter I have on Route 1). Then later that afternoon I drop in to the Madonna Inn for lunch and to check out its David LaChapelle-in-a-K-hole interior of plastic baroque, rococo and Rocky Horror flower arrangements.

Just past Santa Barbara, north of the turn off for Santa Claus Lane, the horizon fills with offshore oil platforms. Not far from here I pull into Ojai, home to Bart's open-air Bookstore: pretty, literary, hippie and all about the outdoors. When it's closed you can grab a book from a street-side shelf and post the money through the letterbox.

That evening, I park up at the Ojai Resort for dinner, where the main event is cocktails just after 8pm in anticipation of the "Pink Moment", when the sunset reflects off the white-streaked cliffs. I miss the whole thing because it turns out that I've been looking at the wrong cliffs, but I still enjoy the local cabernet sauvignon, the filet mignon and a general ambience of rosy pinkness.

The cultural gateway to LA, just an hour from Ojai, is the Universal Studios theme park, home of Spielberg's big rubber shark and the eat-all-you-can fast-food day pass. Fries come with everything, and every other visitor comes supersized. I leave the Mustang in the Jurassic Parking zone and head for the Simpsons Ride, one of the most popular in the Universal galaxy. The highlight of the Simpsons Ride involves your virtual rollercoaster car being sucked into Maggie Simpson's mouth and the aroma of strawberry sweets filling the air. The whole experience is ingeniously conceived, beautifully styled and visually wild: Hollywood magic.

LA is perfect for a convertible; traffic rarely moves fast enough to make wind speed a problem, and while it may sprawl like Dorothy Parker's "72 suburbs in search of a city", it's a glamorous sprawl. At the Hollywood Roosevelt, with its iconic David Hockney fleck-painted swimming pool, the glamour consists of louche, hard-bodied early-twentysomethings, gearing up for a late-night party in the Playboy mansion-style cabanas.

At the Thompson Beverly Hills, the architecture is sleek, pared-down modernism. The crowd is 90210 late twentysomethings with Hollywood smiles and silly little trilbys. At the pink-on-pink Beverly Hills Hotel it's their parents in fedoras grazing on McCarthy salads from the Polo Lounge amidst the A-list and their agents. And at the Andaz Hotel – once the notorious "riot Hyatt", now the most mod hotel in West Hollywood – I feel ever-so-LA by leaving the pool, plugging my iPod into a cardio machine and running for five miles on the spot, overlooking Sunset Strip.

LA is a place for outdoor living. At twilight I sip Sonoma chardonnay at the iconic Hollywood Bowl. Philip Glass is on stage, conducting the LA Philharmonic as they perform his score to Koyaanisqatsi. It's a mercifully smogless evening, and stars twinkle overhead through darkening scarlet clouds while the headlights of slow-motion traffic streak in abstract patterns across a huge screen hanging above the orchestra. In a city designed by for the automobile, it's an evening that sums up so much, so elegantly.

I thought I'd acclimatised to the Californian heat, but my arrival in Palm Springs suggests otherwise. As I head further east the dashboard thermometer goes north, resting exhausted at 117 degrees: top down, air-con-on desert weather. I pass Albert Frey's soaring, angular, mid-century modern Tramway gas station at the city limits and coast through a quick architour of 1950s International Style landmarks. Each one is a signpost to the Rat Pack's jazzy hedonistic playground of yore.

I check-in to the Orbit In, originally Herb Burns' 1947 "ultra modern motor court inn" and now a lovingly restored low-budget B&B with Eames furnishings, Jetsons flourishes and an Orbitini cocktail hour. It's totally Palm Springs, right down to the little Pee Wee Herman bicycles you can borrow to cycle to the nearby Tropicale for flaming cocktails served in a huge half-shell shaped bowl. I finish my road trip with dinner at the Ace resort – the epitome of new-wave Palm Springs, swinging again in fine style. I settle into a booth in the 50s-diner-meets-David Collins-in-Manhattan restaurant and eat posh chilli with cocktails and decobbed corn with cheese, Mexican-street-style.

The restaurant's hostess, Linda Gerard, looks like a Golden Girl with more a hint of Bette Midler and a soupçon of drag, in an acid-floral blouse. She performs a mid-course, six-and-a-half-minute storming version of "Zing went the Strings of my Heart". It's the perfect, final, on-the-road feast; a total trip.

Travel essentials: California

Getting there

*The writer travelled with Air France (0871 66 33 777; ) which flies from several UK airports via Paris to both San Francisco and LA.

*BA (0844 493 0787;, United (0845 8444 777; ) and Virgin Atlantic (0844 209 7777; ) fly non-stop from Heathrow to both cities.

*Hertz ( ) rents the Ford Mustang Convertible from £325 per week.

Staying there

*Andaz West Hollywood (001 323 656 1234; ). Doubles from $224 (£149).

*The Beverly Hills Hotel & Bungalows, LA (001 310 276 2251; ). Doubles from $576 (£384).

*The Hollywood Roosevelt, LA (001 323 466 7000; ). Doubles from $186 (£124).

*Orbit In, Palm Springs (001 760 323 3585; ). Doubles from $133 (£88), with breakfast.

*Post Ranch Inn, Big Sur (001 831 667 2200; ). B&B from $550 (£367).

*Thompson Beverly Hills (001 310 273 1400; ). Doubles from $269 (£179).

*W San Francisco (001 877 946 8357; ). Doubles from $294 (£196).

Visiting there

*Barts Books of Ojai (001 805 646 3755; ).

*Madonna Inn (001 805 543 1800; ).

*Universal Studios (001 800 864 837 725; ).

*Esalen Hot Springs (reservations: 001 831 667 3047).

Eating and drinking there

*Foreign Cinema, San Francisco (001 415 648 7600).

*Ojai Valley Inn (001 805 646 1111; ).

*Ace Hotel Palm Springs (001 760 325 9900; ).

*The Tropicale, Palm Springs (001 760 866 1952).

More information