The drive along the Pacific coast from Portland to San Francisco offers vistas of towering trees and, well, more towering trees. Nature has gone a little ga-ga here, with mysterious forces that can twist vegetation, mock gravity, and give superpowers to a dog. People are similarly smitten: eating bugs, burrowing holes through redwoods, and building museums to house tiny microchips and impossible flying machines.
Freakybuttrue Peculiarium, Portland
Trying its best to uphold Portland's image – the city's unofficial motto is Keep Portland Weird – the Freakybuttrue Peculiarium and Museum is a 21st-century cabinet of curiosities, combining a fringe art gallery, carnival sideshows, a store of strangeness and a cafe. You can pose in an alien autopsy photo-op (you're the one being disemboweled), peer into Portland's largest kaleidoscope, and scrawl phosphorescent graffiti in a motel room where everything is coated in glow-in-the-dark paint. The bold can also join the Insectarian Club by eating an ice-cream sundae sprinkled with crickets and mealworms.
• 2234 NW Thurman St, Portland, peculiarium.com. Open Wed-Fri 11am-5pm, Sat 11am-7pm, Sun 11am-5pm. Free
Evergreen Aviation and Space Museum, McMinnville
This museum has dozens of vintage, priceless aircraft, rockets and spacecraft – but its star exhibit is the Spruce Goose, the world's largest wooden airplane. Built of plywood in the 1940s by obsessive billionaire Howard Hughes, it flew only once. It is so huge that its wings could probably be used as runways by some of the museum's normal-size aircraft, and its insides are littered with blown-up beach balls – Hughes thought they'd help his mega-plane float if it crashed at sea. Also at the museum is a retired 747 jetliner, gutted and turned into the world's most expensive water slide.
• 500 NE Captain Michael King Smith Way, McMinnville, evergreenmuseum.org. Open daily 9am-5pm. Adults $25, seniors $24, children (five-16) $23, under-fives free
Home of Bobbie the Wonder Dog, Silverton
Bobbie look-a-like contest in Silverton
Even on a short list of canonised canines, Bobbie the Wonder Dog is exceptional. He was lost on a far-flung family vacation in Indiana, and six months later hobbled back into town bedraggled and footsore. He had somehow walked 2,500miles, across plains and rivers and mountain ranges, in the dead of winter, to get home. Silverton honours its most loyal resident with an annual pet parade (led by the winner of a Bobbie lookalike contest), a lifesize statue, a mural of Bobbie's life, and a replica of his fancy "Welcome home!" dog house.
• 200 S Water St, Silverton, silvertonbobbie.com. Open daily, free
The Oregon Vortex, Gold Hill
Many so-called "mystery spots" may be optical illusions. The Oregon Vortex is the real deal: nature and physics gone berserk. Far from any town or highway interchange, the Vortex has been spooking holidaymakers since 1930 (and others long before that). Balls roll uphill, brooms stand on end, people seem to grow or shrink by moving only a few steps. Pamphlets available in the gift shop speculate that a giant underground device may produce the weird effects. One man, John Litster, studied the Vortex for more than 40 years, then burned all his notes before his death!
• 4303 Sardine Creek Road, Gold Hill, oregonvortex.com. Open daily Jun-Aug 9am-5pm, Mar-May and Sep-Oct 9am-4pm. Adults $9.75, seniors $8.75, children (six-11) $7, under-sixes free
Trees Of Mystery, Klamath
The entrance to Trees of Mystery is guarded by giant statues of Paul Bunyan and Babe the Blue Ox, popular characters from 19th-century backwoods folklore. Paul, standing 15m tall, greets the public through a loudspeaker in his pocket. Visitors walk a trail to the mystery trees, shaped like pretzels and DNA double helixes, then visit the Cathedral Tree, a semi-circle of six redwoods growing out of a single root, considered one of the most beautiful of redwood spots. The wet, windy climate is supposedly responsible for twisting the trees, and has blown the heads off of Paul and Babe more than once.
• 15500 Highway 101, Klamath, treesofmystery.net. Open daily, June-Aug 8am-6.30pm, Sept-May 9am-4.30pm. Adults $15, seniors $11, children (seven-12) $8, under sevens free
Shrine Drive-Thru Tree, Myers Flat
Early promoters tunneled through several of California's giant redwoods, and tourists continue to pay to make a six-metre journey through a tree. The Shrine Drive-Thru Tree is typical: you pay upfront, then may be dismayed to discover that your SUV is too big to fit through the car-size hole. Laws forbid any new drive-thru trees, so extraordinary efforts are made to keep the few that remain in drivable condition. For those unwilling or unable to drive through, the park offers a consolation Step-Thru Stump.
• 13078 Avenue of the Giants, Myers Flat, redwoods.info/showrecord.asp?id=3947. Open dawn-dusk, gift shop 9am-6pm. Free
Coppola Winery Movie Gallery, Geyserville
Two of California's glamour attractions are Hollywood and the wine country. At the Coppola Winery Movie Museum, you get both. The wines are good, the restaurant excellent, but this is the world's only winery with a pile of skulls, a bamboo prisoner cage, and the armour of Vlad the Impaler – all props from movies by Francis Ford or Sofia Coppola. Part of the fun is trying to identify the films. The car from Tucker is easy, as are Robert Duvall's cowboy boots and cavalry hat from Apocalypse Now. But do you remember 1996's Jack, starring Robin Williams? The Vlad armour is from 1992's Dracula. And there's memorabilia from Sofia Coppola's 2006 Marie Antoinette.
• 300 Via Archimedes, Geyserville, franciscoppolawinery.com. Restaurant 11am-9pm, tastings 11am-6pm. Movie gallery free
Computer History Museum, Mountain View
The world's first computer mouse in a wooden case
Silicon Valley is known for its grey office parks, but it's also the home of the lavish Computer History Museum: 19 galleries of super-geeky wonders. Some are artful enough to grace any museum, such as the world's first computer mouse (in a wooden case) and the 1969 Honeywell Kitchen Computer, as big as a sofa, with a cutting board and cathode ray tube for viewing recipes. Don't miss the miniature model of Norad's four-floor Soviet bomber-tracking megacomputer, complete with tiny hand-painted console jockeys at their boxy workstations and equipment bays. By the time the real thing was completed, it was obsolete.
• 1401 N Shoreline Boulevard, Mountain View, computerhistory.org. Wed-Sun 10am-5pm. Adults $15, seniors $12, under-13s free
Cupid's Span, San Francisco
Did Cupid leave his heart in San Francisco, or just his arrow embedded in its ticker? These questions come to mind when viewing Cupid's Span, a 42m-long golden bow and 18m-high red-feathered arrow, each half-buried in the ground near the foot of the city's Bay Bridge. It was designed in 2002 by pop artist Claes Oldenburg and his wife Coosje van Bruggen, who said its curiously positioned bow ends evoke images of ships in the harbour, the string is a tribute to the nearby suspension bridge, and the hidden arrowhead makes the sculpture less violent.
• Rincon Park, San Francisco, oldenburgvanbruggen.com/largescaleprojects/cupidsspan.htm. Free
Lombard Street and Vermont Street, San Francisco
Millions of tourists have slowly snaked their way along Lombard Street in San Francisco, thinking that they were on the crookedest street in the world. Wrong. They weren't even on the crookedest street in the city. That would be Vermont Street, which wiggles its way down Potrero Hill between 20th and 22nd Streets. Its seven switchbacks are far more disorienting and claustrophobic than Lombard's, because they're wedged into a tree-canopied alley. And, unlike on Lombard, there's never a queue to drive down it – except during the street's annual Bring Your Own Big Wheel race in April.
Ken Smith and Doug Kirby are the editors of Roadsideamerica.com, a guide to more than 9,000 offbeat tourist sights in the US and Canada
• For more information on holidays in the USA, visit DiscoverAmerica.com