As I fly into the state's south-east, the Great Plains below resemble brain matter but, when I land, my guide for the day informs me Billings is known as the armpit of Montana. Andy Austin is a baby-faced giant with a GSOH, a slight hobble from over-commitment to college football and equal doses of passion and skill for landscape photography. He shows me some examples; all love letters to his stunner of a home state.

An hour from the city, we drive onto Crow Reservation where about three quarters of the members of Apsaalooke tribe live – either on or near the reservation – and most speak Crow as their first language. I'm here to see a re-enactment of the Battle of the Little Bighorn, which took place on a similarly hot late-June day back in 1876.

Custer Battlefield Museum stands on the former site of Sitting Bull's camp and one of the largest gatherings of Native Americans recorded – more than 1800 warriors of the Sioux, Cheyenne and Arapahoe nations. The museum's collection includes an 1870s Sioux doll, 7th US Cavalry spurs, Custer's beaded gauntlets, a Native American war shirt embellished with human epidermis and hair, and more than 100 exquisite monochrome portraits by photographer David F Barry.

At the Trading Post Cafe, we lunch on soup and fry bread and cherry pie. It's opposite the entrance to Little Bighorn Battlefield National Monument where we return later in the afternoon for an objective patio battle talk on what's also known as Battle of the Greasy Grass and Custer's Last Stand.

For 20 years the Real Bird family have hosted a Battle of the Little Bighorn re-enactment, significant for being one of the last armed efforts of the Northern Plains people to preserve their traditional way of life. And, the commentator says over the loudspeaker as we find space on the open bleachers, "one of the greatest victories of the American Indians".

The Star Spangled Banner is live on electric guitar, a herd of unsaddled horses canter the field then the narration and action officially begin. Although historic military uniforms always look unauthentic to me, the body-painted riders gallop bareback as though glued to their horses and the spoken words are transportative. They paint life on the Great Plains before Europeans "when we were free to roam as our lodges moved to follow the mighty buffalo herds that followed good water and good grass" and explain events leading up to the Greasy Grass from the point of view of those who won that battle but lost the war.

The next day I'm expected in the Sawtooth Mountains before dinner and leave Billings mid-morning for an easy day on the road. Montana is the country's fourth largest state but with one of the lowest populations. It borders Idaho, Wyoming, the Dakotas and Canada and resembles an RV that's crashed travelling west. Although nearly half is prairie, the early Spanish explorers called the area Montana del Norte and it stuck. The north-west has more than 100 named mountain ranges, three quarters of which are part of the Rockies.

Montana is a place in the US where introverts are allowed to be introverted and Triple J Ranch is a dude ranch where guests don't get treated like dudes. It's been in the Barker family for more than 40 years and has a homely feel with private cabins and staff from across the country.

Jimmy Nemeth from Cleveland, Ohio, tells me he "caught the bug" spending a week at Triple J with his mother the previous year. He returned this summer to wrangle. Part of his job involves loading up mules for week-long wilderness pack-trips, which the Barkers invite me to come back for sometime.

But for now I'm happy with a half-day ride alongside the summer rush of Sun River in Western wear and Blunnies on a horse called Ringo. We're led with quiet competence by Hayley Barker – she'll manage the ranch one day – who had to be coaxed at the campfire dinner last night to tell her tale of stalking a bull elk on a freezing cold ridge as a grizzly stalked her. Another wrangler, Megan McGrade, accompanies us. She spends university semesters aching for summertime among the wildflowers and pines and folded scree-sloped mountains.

Sun River Valley is the sort of landscape you could put in a clear plastic sleeve and use as supporting evidence in defence of why so many Americans haven't got a passport.

After two nights I return to the plains that, for a day, act as an empty canvas for my imagination of prehistory; a time of receding inland seas and shifting shorelines as the continental crust rose and fell and reptiles evolved. Montana's fossil beds have provided valuable snapshots of life during the Jurassic and Cretaceous periods of 200-65 million years ago, especially the nest of baby dinosaur bones found in 1978 by Marion Brandvold. Her son is now a palaeontologist who offers introductory digs from Two Medicine Dinosaur Centre in Bynum.

On the drive out to the first site, David Trexler defines palaeontology as the science of "learning from the past to better protect our future". Dinosaur survival on the planet for 150 million years suggests to Trexler we could learn a thing or two from the creatures, so he's written a book about climate change from a palaeontological perspective.

In a cow paddock, where a gravel road conveniently runs through a dino bone bed, we're taught what to look for in terms of colour, texture, shape. The youngest in the group points to a whopper. "Actually, that's Bessie," she's told gently.

From Bynum I head north to Browning, but overshoot and end up at the eastern entrance to Glacier National Park where a leggy black bear lopes across in front of me on the otherwise empty road.

My night at Tipi Village on Blackfeet Reservation coincides with a group of high schoolers from nearby Great Falls on an intertribal school excursion. About 65,000 people in Montana identify as Native American. Josie tells me she's Arapahoe. Maria is Blackfeet and Sioux. There's laughter as Lorenzo reels off that he's "Blackfeet, Chippewa, Cherokee, Sioux…" I wish I'd asked their last names. They tell me about dream catchers, the sun dance, vision quests and answer all my sweat lodge questions.

I drop off easily that night as the fire in the centre of my expansive canvas tipi reduces to coals. Outside there's a gentle breeze and a full moon. "My grandpa calls the tipi the circle of life," Shanell had said. "When you sleep, your dreams move around freely and go out the top".

For the Blackfeet, Glacier's peaks are the backbone of the world. Its ancestral rocks, possibly a billion years old, were raised 80-55 million years ago. Since then, glaciers have sculpted the mountains into the dramatic shapes we now see.

Over two days I explore this park by raft on the Flathead River and on foot to Piegan Pass with Glacier Guides. Our 14-kilometre guided hike begins near Logan Pass just off Going-to-the-Sun Road at about 2000 altitudinal metres. It's a gradual ascent to the pass with Piegan Glacier in full view across the valley. I fall into a fresh air version of an aeroplane conversation with an American woman who's also lone wolfing it around Montana.

Our guide, Sarah, is a self-confessed plant nerd and can name them all. She also explains there are now only 25 remaining glaciers of the 150 here when the park was established in 1910. Due to climate change they could all be gone by 2030. This makes me think of Trexler's book and its cleverly portentive title Becoming Dinosaurs. 

TRIP NOTES

MORE INFORMATION

visitmt.com; discoveramerica.com 

GETTING THERE

Fly United from Sydney or Melbourne to Billings or Glacier Park International Airport. Connections are in Los Angeles or San Francisco and then Denver. See united.com

Hire a car through DriveAway Holidays. See driveaway.com.au 

STAYING THERE

Dude Rancher Lodge, 415 N 29th St, Billings. Rooms start from $US75 a night. See duderancherlodge.com

Triple J Wilderness Ranch, 91 Mortimer Rd, Augusta. A 6-night stay starts from $US2250 per person. See triplejranch.com

Lodgepole Gallery & Tipi Village, Hwy 89, Browning. $US65 for the first person in the tipi and $US15 for each additional person. See blackfeetculturecamp.com Glacier Guides Lodge, 120 Highline Blvd, West Glacier. Rooms from $US168 a night during summer. See glacierguides.com

Elspeth Callender travelled as a guest of Montana Tourism.

More things to do in the Montana summer sun 

GET ON THE DINOSAUR TRAIL

If really old bones rock your world, order a prehistoric passport and plan your palaeontological journey through Montana visiting some or all 14 dinosaur exhibits and fossil sites. See mtdinotrail.org

GO TO A POW WOW OR FAIR

Native American gatherings of song, dance and celebration and are held annually, such as North American Indians Days in Browning and Crow Fair near Bighorn Canyon. See visitmt.com

SEE A RODEO 

Montana has a rich rodeo heritage and its cowgirls and cowboys continue to compete across the state in barrel racing, steer roping, bronc riding and bull riding. See visitmt.com

TRAVEL GOING-TO-THE-SUN ROAD

Pack a picnic and make a day of driving this historic 1930s highway through Glacier National Park. Alternatively, hop on a Sun Tours coach for a Blackfeet perspective. See glaciersuntours.com 

VISIT YELLOWSTONE 

In 1872, Yellowstone became America's first national park. Although predominantly in Wyoming, three of the park's five entrances are in Montana. The Beartooth Highway is a particularly scenic route.