Yellowstone: the very word conjures up images and preconceptions. Try a word association starting with Yellowstone and the chances are that most people will answer “Old Faithful” within the first 10 seconds.

To be fair, Old Faithful IS Yellowstones’s most iconic attraction. It erupts every 68-98 minutes, a schedule can be found within the visitor centres (plus or minus 10 minutes) and you can tell when the next eruption is due by the size of the crowd on the seats around it.

We had arrived, having driven Yellowstone for the day, at around 5.15 pm and still with two hours to go to get back to our accommodation just outside Gardiner, at the park’s North entrance. We were relieved to find a huge crowd and the word was “within the next 10 minutes…”

5, 4, 3, 2, 1… and Old Faithful shoots around 140 feet into the air, keeping up the eruption for a few minutes, long enough for everyone to take a couple of million photos.

Although it’s Yellowstone’s most famous attraction, in truth it’s not the most astonishing and nor is it the most attractive.

We had a discussion about our favourite Yellowstone attraction:

Was it the Morning Glory Pool or the upper geyser basin in its entirety? The pool has a 15 foot(ish) aquamarine centre, encircled by yellow and gold. It’s situated along the boardwalks of the Upper Geyser basin, which are walked from Old Faithful, the crowds dissipating as soon as you leave the main attraction. The boardwalks wind among the steaming earth’s surface, round the geysers, which erupt anything from every five minutes to every few months, and past the varied colours of the rocks, pools and bubbling vents.

Was it the Norris geyser basin, with extensive board walks through the geysers and multi-coloured simmering fumaroles emitting sulphurous odours?

Or was it the Mammoth Hot Springs, just inside the northern entrance to the park? Mammoth contains a variety of volcanic features with exotic sounding names: the Inside-out Cave, the Canary Spring, the Devil’s Thumb, the Mound and Jupiter Terraces to name but a few. In places Mammoth Hot Springs looks as if someone has dropped a giant bomb and has thus created an otherworldly haunting beauty. Yellowstone was a super-volcano which erupted 600,000 plus years ago, but who’d have expected it to still look like this?

It might even be the non-volcanic features of Yellowstone, such as the Lamar Valley (The Serengeti of America) where herds of bison wander and create “bison jams” on the road, and where road pull-ins are full of cars and trailers, their occupants scanning the meadows for bears and wolves.

Personally, I settled on the Grand Canyon of the Yellowstone. Here a steep hike downwards, all the time watching the chipmunks and squirrels scampering through the trees, finally revealed an observation point directly above the Lower Falls of the Yellowstone River, The upper falls visible along the canyon in one direction and the V-shaped yellow canyon, slightly obscured by the waterfall spray rainbow, in the other.

We’d started the trip at Kalispell in Montana, intending to drive north to south, from the Glacier National Park, through Yellowstone and Grand Teton National Parks, the Flaming Gorge National recreation area and down through four states: Montana, Wyoming, the north eastern corner of Utah and finishing in Colorado. We were staying in a mixture of Airbnb rentals, independent hotels and lodges and finishing in a friend’s condo in Frisco, near Denver.

The first task was to purchase a year-long “America the beautiful” National Park pass. A year’s pass for a three week trip sounds a bit extravagant but at $80 for a carful of four people, it’s by far the most economical. There are no parking fees in the parks, so $80 for a year’s access – compare that with UK parking rates!

Sandwiching Yellowstone, we spent a few days visiting both Glacier and Grand Teton National Parks. The two parks have similarities: soaring peaks, hidden lakes, glorious views, ample hiking opportunities… and bear warnings. Bear warnings? Virtually every trail has an information board; “You are entering bear country”. “Be bear aware”. “Make lots of noise”. “Carry a bear spray”.

Bear Spray? If we ever encountered a bear close enough to have to use the pepper spray, we doubted if we’d have enough presence of mind to pull out the canister, remove the protective trigger and spray the bear with it. Luckily, we never had need to do this, although on one hike a walker coming from the opposite direction warned us that two bears had just been spotted on the path ahead. By the time we got to the indicated area, there was no sign of them.

It’s not that we didn’t see bears. In Glacier we saw mother and cub grizzlies, luckily at binocular distance. And on the three occasions we encountered bears at close range, it was always from the safety of the car. Bear spray not needed!

We saw lots of other wildlife too: Bison (inevitably), moose, elk , pronghorn antelope, mountain goats, American bald eagles, hummingbirds and the ubiquitous chipmunks and squirrels to list but a few.

One of the most recommended activities in Glacier is to drive the “Going-to-the-Sun Road”, but if you’re entering from the west and you intend to venture more than a few miles into the park, it’s impossible to avoid it. The name gives the game away; steeply upwards, winding and narrow, up to an elevation of around 9,000 feet, it’s not for the faint-hearted driver. But for drivers brought up on narrow British roads, it’s a wonderfully scenic not-too-worrying experience.

After leaving Grand Teton we headed south through Wyoming, to a brief break-up-the-journey stop at Red Canyon, part of the Flaming Gorge National Recreation area in North Eastern Utah. In contrast to the Going-to-the-Sun road, this drive was long, flat and boring. The drivers longed for a bend in the road or just another vehicle to break up the monotony. But Red Canyon made that worthwhile… an easy hike along the rim, spotting big horn sheep, mule deer, woodpeckers and hawks, and the deepening red of the canyon in the setting sun.

Just in Utah, on the border with Colorado and part of both states, is the Dinosaur National Monument. This was established in 1915 by President Woodrow Wilson when over a thousand fossilised dinosaur bones were found embedded in the quarry here. Today the whole quarry wall is displayed behind protective glass. The entry fee would be $25 per vehicle but as we’d already purchased the annual pass , there was no more to pay to see this astonishing collection. And as it was just a few miles off our route, the opportunity to call in was too good to miss.

The final week of this trip was spent in Frisco, Colorado about an hour and a half’s drive west of Denver. This small town with a population of around 2,600 provides an ideal base from which to explore the skiing resorts of Breckenridge, Vail and Aspen. But as it wasn’t skiing season, these towns were of limited interest.

More interesting was the Silver Plume to Georgetown loop railway. This narrow gauge railroad was opened to link two small mining towns in the 1870s, The two towns are only a mile apart but as their respective elevations differ by 600 feet, it wasn’t possible to construct a straight line rail connection. Instead the engineers created a three mile loop so that the track winds steadily round on itself. Today it’s a rideable tourist attraction as the little steam engine and carriages corkscrew their way through the scenic countryside.

This also provided the opportunity to visit Georgetown itself. A quirky little town with a quaint “Olde Englishe” tea room, “ The Dusty Rose”. With odd window displays (“caution: Do not feed the zombies”, 1870’s style shops selling strange items (Reese’s chocolate-covered caterpillars) and the perfectly preserved Hotel de Paris, now a museum. This hotel was built by the entrepreneurial Louis Dupuy and finally completed in1890. Louis came to Georgetown to mine for silver but a mining accident put paid to his dreams, So he set about building the hotel, which, after Louis’ death, was handed on several times, each time complete with all fixtures and fittings and is now open for a guided tour of this original hotel and to hear details of Louis’ interesting backstory.

Also from Frisco we took the opportunity to hike Mayflower Gulch. An easy hike for locals, it’s only around a five mile round trip, with a steady elevation gain of just over 1,000 feet. But as it starts at 11,000 feet and finishes at 12,000, it’s one serious lung stretching slog for sea levellers like us.

With only the drive back to Denver airport remaining, there was still time to fit in a couple of spectacular sights. Mount Evans, at 14,271 feet, is a great place to overlook many of Colorado’s 58 over 14,000 foot peaks. It’s also served by a road to the top; or used to be. These days the final 1,400 feet of winding road is closed to traffic and terminates at Summit Lake. Although this is “only” at 12,836 feet, it’s still a great place to see for miles across Colorado.

Along Interstate 70, the motorway which cuts through Colorado west to east and leads to Denver airport, is a turn off to Red Rocks natural amphitheatre. This has been used as a concert venue by almost everyone in the music business and was the site of one of the Beatles’ first US concerts. Its natural red rocks make for dramatic setting and the amphitheatre and museum are free to wander around when there’s no concert on.

With only time left to kill at the airport, we discussed the highlights of the trip. There were so many that the whole of the flight waiting time was filled. Unanimously, Yellowstone occupied the number one slot. But the debate over which was the most spectacular of its many diverse areas will last the rest of our lives.