The Lycra-clad sucker puffing and panting up the hill double takes in disgust as he is overtaken. He's probably thinking that this conquistador is far too overweight to be cycling with that speed and ease, especially given that virtually no effort seems to be going into the pedalling.
The poor, sweaty sap would be entirely correct, too. This, however, is the joy of an e-bike, gleefully slipped into the top assistance setting and with the throttle fully depressed. Freewheeling uphill, it turns out, is tremendously good fun.
It is not necessarily the sort of good fun that Las Vegas is immediately associated with, though. And it shows the advantage of using Nevada's good times capital not just as a destination in its own right, but as a base for exploring the US south-west's wild, rugged landscapes.
Red Rock Canyon, where this piece of two-wheeled fraud takes place, most certainly ticks the wild and rugged boxes. Saw-toothed peaks jut upwards; furious red colours betray the presence of iron in the rock beds that were once on the sea floor; slowly-eroding chunks of the mountainsides look like they're ready to break away and stand alone as finger-like towers. It's just 28km west of the Las Vegas Strip, and gives a strong hint about the land that the miraculous Vegas mirage was constructed upon.
Red E Bike Tours had to fight long and hard to get the necessary permits to operate in Red Rock. Even before setting off, participants are given a stern lecture on the desert tortoise. If they're startled, they can urinate their vital water supply out, then die of dehydration. Touching one, apparently, is an imprisonable offence – which leads to bizarre visions of rival tortoise-touching gangs facing off in Nevada penitentiaries.
The bikes are locally made, and serious bits of kit. They've got hydraulic brakes, four motorised settings, and pedal assist – which can make anyone pushing down half-heartedly with the right foot feel like they've suddenly developed superhuman powers. There are also screens showing just how fast you're going, which makes it very tempting to attempt to break the park's vehicle speed limit of 35 miles per hour. Clocking in at 28.5mph (46km/h) on a downhill stretch feels both tantalisingly close to the target and a bit iffy with a sharp-ish corner coming up.
The "Canyon" part of the name isn't exactly accurate. There are realistically a series of nine canyons, and the loop road heads through a valley between them. Little more than scrub and cacti grow on the hillsides, leaving the canyon walls to dominate in their full multi-strata glory.
But where the spaces are less wide-open, there are more signs of life. At Willow Springs, big-horned sheep can often be spotted, and trees fight their way above the level of the stunted bushes. There are also rocks with giant purple swirls, looking like super-sized, free-form tubs of raspberry ripple ice cream.
It's the brown-black veneer that partially covers them that is of most interest, though. This combo of rain, mud and bacteria would be used by Native Americans to tell stories on. And paintings can still be seen there. Five red hand prints are visible on the side of the rock, but the Southern Paiute people who traditionally inhabit the area say they didn't create them. Who did is a mystery, but it is reckoned that it would have been a tribe who lived in Red Rock about 2000 years ago.
The last stretch of the 25.5km circuit is a glorious freewheel downhill before joining the most American of highways. The horizon is a panorama of multi-coloured sandstone, the sky huge and fiercely, unsullied blue. The freedom of the wide open space is rather electrifying.
Considerably more claustrophobic is the Techatticup Mine in Nevada's south-western corner. It's the oldest and richest gold mine in southern Nevada, and still has plenty of gold deposits inside it – the problem is that they're worth less than it would cost to extract them.
Gold was first discovered in Eldorado Canyon in 1853, and eight years later Paiute Indians showed miners a large gold vein in return for "techatticup" (thought to mean "bread" or "hungry"). It is now run as a tourist operation, with the suitably wild west surrounding buildings popular for filming movies and album covers.
The original company store and dining hall now contains a mind-boggling collection of memorabilia and other oddities. Stuffed animal heads, Indian jewellery, old Coca-Cola bottles, metal barber's chairs and tobacco tins have been hoarded and allowed to grow a coating of dust. The spare room, meanwhile, is proper double-take territory – the owners have filled it with life-size alien models.
The tiny settlement is highly atmospheric, and family-run. And it's one of the clan – Indiana Jones lookalike Gabe Werly – who leads the tours into the tunnels. About 5km-worth have been excavated into the mountainside, and they weren't made any bigger than they had to be. This makes for cramped, hunched shuffling inside.
But the donkeys had it worse. "They were hog-tied and put into leather bags, then lowered down into the mine," says Gabe. "They would live there for three years."
Near one of the larger quartz veins is a model of a man with an iron peg through his head. Apparently this is based on a real death in the mine – an explosion blasted the metal straight through the miner's forehead.
It was by no means the only death in these parts. Miners refused to work alone due to the supposed ghost of a colleague they hunted down and killed, following the duplicitous owner's spreading of rumours that the unfortunate was planning to poison the water supply. That same owner had his business partners poisoned with strychnine once a particularly lucrative chamber was discovered inside the mountain.
"There were 70 people in the graveyard before a single person died of natural causes," says Gabe. "Back then, murder wasn't enough to get a sheriff here from 200 miles away."
He turns off the electric lighting so that the mine can be seen as it would have been back then. "You got one candle a day. Some would blow it out and work in the dark so they could take the rest of the candle back home," says Gabe.
He then blows the candle out, and it is terrifyingly dark. "No wonder people thought there were ghosts down here…" he adds with a little too much glee.
The Red Rock and Eldorado Canyons may make for satisfying excursions from Las Vegas, but the big boy is within easy reach too.
The Grand Canyon is about three hours of hard driving from Vegas, but it's a darned sight quicker by helicopter. The Top Gun soundtrack blares out through the headphones as Maverick Helicopters' eight-seater chopper rises above the bottom end of the Strip. The ridiculously supersized resorts line up below, but the edge of the city limits quickly come into view.
From the air, it's far easier to see how the city has been claimed from the desert. Stark mountain ranges crumple up around it, parched and clinging to scraps of vegetation like desperate fig leaves.
But then comes the deep blue of Lake Mead, which spills into the craggy mini-gorges of the landscape, following nature's paths after one of the most dramatic human interventions of all time. The colossal Hoover Dam, which blocked up the Colorado River in order to provide drinking water and hydroelectricity, used up more than 5 million barrels of concrete – enough to build a two-lane highway from San Francisco to New York City.
From above, the dam looks deceptively small, but the sprawl of the lake is a better indicator of its impact.
But then mountains look smaller from above too. There's a hiking trail up Black Mountain that looks like it should take a couple of hours, but the pilot says it's a brutal all-dayer.
The landscape gets about about 7.5-13 centimetres of rain annually, and the dry river beds are formed by flash-flooding. Cows, donkeys and horses that were brought in by miners and dam-builders have been turned loose, growing into hardy wild populations.
But all the rubbly mesas and plateaus on the way descend into inferiority once the helicopter enters the Grand Canyon. Walls 1.2km high, lined by horizontal layers of sand and sediment that were once the sea bed, are unabashedly intimidating. The splintering of smaller canyons off the main one creates a much bigger picture than the one perceived before arrival.
The chopper touches down on a ledge high above the Colorado River but well below the rim walls. As the propeller blades slow down, there's only cacti for company. The neon seems an awfully long way away.
United flies from both Sydney and Melbourne to Los Angeles, connecting on to Las Vegas. See united.com
The Cosmopolitan is a prime example of the new breed of Vegas hotels, with slick, modern design rather than cheesy theming. Rooms cost from $US258 a night. See cosmopolitanlasvegas.com
Red E Bike runs three-hour electric bike tours of Red Rock Canyon for $US99, including pick-up from Las Vegas hotels. See redebike.com
Eldorado Canyon Mine Tours runs daily $US12.50 tours of the historic Techatticup mine, about 45 minutes' drive from Las Vegas. See eldoradocanyonminetours.com
Maverick Helicopters offers its four-hour "wind dancer" heli tour into the Grand Canyon for $US544. See maverickhelicopter.com
David Whitley was a guest of the Las Vegas Convention and Visitors Authority and Travel Nevada.