Even in a nation of extroverts, Jesse is exceptional.
Our guide in Grand Teton, one of the American West's great national parks, is as expansive and colourful as the country he shows us around.
Not long into the tour, the impossibly beautiful wooden Chapel of the Transfiguration comes into view; meadow ahead, mountain behind. An enormous bus emblazoned with "Christian Tours" is parked nearby.
"You're allowed to ring the bell," Jesse tells us. "But it is loud."
Of course, one of our party rings the bell, which hangs above a boardwalk approaching the chapel. Jesse was right. Yes, the bell, when eventually it goes off, is extremely loud, booming under the Wyoming sky.
Inside the chapel, dozens of 60-somethings wearing an array of anoraks gather. Behind the pulpit, a window frames the serrated range of the Grand Tetons. "Y'all got a song leader?" Jesse asks immediately on entering the chapel full of strangers.
He strides to the front of the chapel, and to the astonishment of the six Antipodeans in his tour group, starts singing.
"Amazing grace! How sweet the sound, that saved a wretch like me!
"I once was lost, but now am found, was blind, but now I see."
Some of the tourists sing along too. Jesse continues for a few verses, ends to applause and exits as quickly as he arrived.
The euphoria dissipates from the tour bus people's faces. Maybe the loud bell annoyed them. Maybe they're just annoyed about having to get back on their bus.
We too have to get back on the road. But it's no chore. Distances are vast between the points of interest seen on maps - ranches, lodges, historic sites. The sights between are less predictable. Already today we've seen our first bison - languid big bovines that own the roads and seem without any worries in the world.
Soon we're at Jenny Lake, where we're told grizzlies sometimes hang out. The air is clear, the skies blue. A young family pull out a canoe and take to the water.
Soon after, Jesse stops again. We take a short hike and find ourselves on a big escarpment rising from a vast, flat basin. The view resembles what the Great Rift Valley must look like.
The American West's national parks are frequently overwhelming. The loudest voice gets swallowed up in the big sky. A few moments alone, or in silence, have a profound and peaceful effect. The only problem is eventually having to leave.
At the heart of Grand Teton is Jackson Hole, a valley around which mountains, most notably the Grand Tetons, rise up. The Tetons have some of North America's oldest rocks, but are among the youngest ranges. Over the eons here, tectonic plates collide, subside, rise up again, and the effects are spectacular.
It's not just dazzling natural scenery. As with the Chapel of the Transfiguration, the human imprint here has been made thoughtfully maintained, carefully in keeping with a desire to blend in.
Grand Teton has several sites rich in Old West folklore. At the Cunningham Cabin, we learn about an 1899 gunfight between a Montana posse and two horse thieves, who were killed and buried in unmarked graves nearby.
The Cabin, like many buildings in the park, is slowly fading away. Soon, on the geological timescale at least, the elements, vegetation and odd elk or buffalo will rule again.
There are more developed areas, such as Colter Bay with its marina on another of Grand Teton's lakes, but here too the vibe, at least in late summer, is not at all hectic.
We have lunch at a friendly diner that offers Bison Burgers, then find ourselves at Teton Village, a winter-sports haven where we're told a visit on a "tram" awaits us. The aerial tram rises 1262m in a quarter-hour trip to the top of Rendezvous Mountain, 3185m above sea level.
There's a waffle shop at the top, open even outside the ski season. The air is clear, thin, invigorating, the views impressive.
The seismic upheavals that formed the jagged, big-sky landscape round here are still at work further north.
Several hours' drive away, to the Wyoming-Montana border, is the oldest, most famous of America's national parks: Yellowstone, of Yogi Bear and Old Faithful fame.
The big ol' bison are a lot more common here. Just outside the yellow, wooden Lake Yellowstone Hotel, herds wander freely.
Later, Canyon Bridge over the Yellowstone River gives a hint of what's to come, and we're soon at what they call here the Grand Canyon of the Yellowstone. Though much of the west has been dry lately, the river and waterfalls in the park still surge, enthralling onlookers.
A freakishly tall jock from St Louis hikes around rapidly to see as much as possible. When he stops at the spot overlooking the falls, he's popular with tourists contorting themselves to get the best angle, the highest view of the falls.
"My wife said we need someone taller to take our photo," a stout middle-aged pastor from somewhere down south tells the tall man. "I told her: I think I know a guy who can help."
Yellowstone, in parts, smells like Rotorua: a combination of gunpowder and egg-eater's flatulence. At one stop, we see the remnants of a boiled egg. The previous tour group clearly had an interactive smell-comparison activity.
A technicolour landscape like something from a Dali painting greets us at Fountain Paint Pots, where dozens of geothermal features skirt the boardwalk.
Our guide, Tom from Wisconsin, works for Yellowstone and though he's just been here a few months, has vast knowledge of the landscape, the geysers, the myriad geothermal features. He only gets annoyed when he sees people ignoring signs to stay off the often dangerous and strangely delicate formations here.
Soon, we're at the alpha and omega of Yellowstone wonders - Old Faithful. A crowd, about 1000 people, gather like pilgrims at a shrine, waiting with iPads and cameras on alert, to watch a minute or so of steam shooting into the low blue Wyoming sky. Old Faithful is an interesting sight, but just one of many beautiful spots in Yellowstone.
We cross the Continental Divide and stay the night in Canyon Village, near the Upper Falls of the Yellowstone River.
Our lodge has just opened, and there is construction going on. A building crew from Missoula, Montana, have been working overtime and just head home as we prepare for dinner at a restaurant a few minutes' walk away.
The elk bratwurst here goes well with a serving of dark Moose Drool beer. The lodge has a big, pleasant lounge and bar.
The sole Kiwi visitor in the group is having a good time but on leaving, soon realises it's pitch black outside and he can't remember how to get home. At least the galaxies are visible in stunning detail, no light pollution here, not a sound, not a headlight nor neon sign anywhere. As time passes, more wrong turns are taken. Visions of grizzlies and wolves pass through his head. Oh well, if a wild beast of Wyoming mauls him to death, he'll die under a clear sky spattered with a million stars.
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This year marks the centenary of the US National Parks service. Herald Travel will be running more stories on these amazing destinations through the year.