As I teeter on the 225-foot-high railroad trestle, a vigorous wind laps at my back. The bridge ends abruptly right here where I’m standing, about 600 feet across the 2,000-foot-wide Kinzua Gorge in northwestern Pennsylvania. Gingerly, I scoot toward the edge of the bridge without lifting my feet and peek over the railing at the end of the trestle, not really wanting to look down.

But I have to. That’s why I’m here: to see this bridge to nowhere.

Details: Pennsylvania Route 6

For more than a century, this was the Kinzua Viaduct, once the longest and highest railroad bridge in the world. Now it’s an outdoor observation walkway called the Kinzua Bridge Skywalk.

Far below, on the canyon floor, corroded steel towers lie twisted on the ground like a toppled toy Erector set, remnants of the bridge left behind by a 2003 tornado that destroyed half of it, leaving just the part I’m standing on.

Before I can fully take in the surrounding views of lush rounded mountains carpeted in green, something comes hurtling at me from behind: my 2-year-old. He’s bounding across the 12 glass panels installed in the floor of the bridge, giving a vertigo-inducing view down to the gorge below, without the faintest hint of fear.

“Mama, want to dance with me?” he asks, swaying in the wind.

And I’d thought that the stargazing the night before and the sand castles yet to come would be the magic of this road trip. But emboldened by my son, I release my hold on the railing, take up his hands and move to the glass floor. For a moment, we’re flying.

It’s a relief, because all day we’ve been driving. This is day two of a three-day journey with my husband and our two toddler sons — ages 1 and 2 — from Scranton to Erie along the surprising, quirky and utterly authentic Pennsylvania Route 6.

Like the viaduct, Route 6 once boasted a superlative: the longest cross-country route in the United States.

The Pennsylvania portion is only about 400 miles of the meandering 3,652-mile route from Provincetown, Mass., to Long Beach, Calif. Connecting the East with the West in 1937 and fully paved in 1952, Route 6 remained the country’s longest road until 1964, when a new western terminus in Bishop, Calif., shortened it to today’s 3,227 miles and made it second in length to 3,345-mile U.S. 20 between Boston and Newport, Ore.

Pennsylvania’s section shimmies across the northern swath of the state, from New York to Ohio, rolling over mountain passes, flirting with the Susquehanna River and chasing railroad tracks. Heading west, as we did on our drive, the road can unfold like a cross-country trip in miniature, moving from the eastern industrial centers around Scranton through central farmland and western wilds, including Pennsylvania’s own “Grand Canyon,” and on to the eastern coastline of Lake Erie. With roadside food, great hiking, museums and even a random site related to Marie Antoinette (say what?!), it sounded like a road-tripper’s delight.

An idiosyncratic route

My husband, Michael, and I plotted out an itinerary: a logging museum and Grand Canyon hiking for him, night-sky stargazing and classic diners for me. Then we threw in several spots for the kids — trains in Scranton, a beach in Erie, and parks and ice cream in between.

At least that’s what we hoped to find. But first we had to find Route 6.

The first indication that we were heading away from the tried and true was the 15-minute fight we had with our GPS. We caught Route 6 at Clarks Summit, just north of Scranton, but not before the GPS seemed to suggest every interstate, highway, street and bike trail nearby as more efficient. And probably, they are: Even that peripatetic soul Sal Paradise, the narrator of Jack Kerouac’s novel “On the Road,” eschewed the idiosyncrasy of Route 6 when planning a cross-country trip, opting for more direct, trafficked routes. We ultimately pulled the plug on the GPS and dug out the paper map.

Our first stop that morning had been Steamtown National Historic Site in downtown Scranton, where our train-iac toddlers got to go gaga for choo-choos. But this site isn’t just for kids. We enjoyed exploring a working steam-train yard and riding an excursion train through town.

We’d barely gone a mile on Route 6 when Michael hastily swung the car to a stop at the Glenburn Grill and Bakery. As soon as I saw the wraparound bakery case, I knew that this road trip was on: It was a Pennsylvania treat-pot. We loaded up on hand-size chocolate-chip and peanut-butter cookies, moist Dutch cinnamon coffee cake, a cake that evoked Hershey’s Almond Joy, and a little yellow bite of heaven that was a dead ringer for Philadelphia’s famous Tastykake Krimpets (according to my husband, a Philly native and Tastykake aficionado).

In addition to the sweets along the way, the route offered a pleasant aura of Pennsylvania-ness. Unlike a drive through New England, with its pressed corners and clapboard crispness, or a journey across the leisurely rural lushness of the South, this route takes you through towns historically fueled by industry — lumber and coal, oil and railroads — and the regions still churn with that come-as-you-are resourcefulness.

Towns such as Tunkhannock and Wyalusing emerged from the trees, with tidy main streets — often Route 6 itself — featuring gift and antiques shops, restaurants and Victorian houses that were handsome but not showy. Between the towns, industry chugged on, with railroad lines and farming, low-impact logging and crews drilling for natural gas.

This isn’t the Hamptons or Disney World. There’s no jet-set destination hub or shiny packaging. It isn’t even the Poconos or Dutch Wonderland, with their regional claims on fun. This is choose your own adventure. Into motor sports? Camp and four-wheel your way across Route 6. History’s your thing? Stroll through museums, historic sites and cultural societies all along the road. Foodie? There are enough diners, drive-ins, bakeries and coffee shops along the way to fuel a gustatory pilgrimage.

For us? We wanted the smorgasbord.

Small towns and night skies

Our next stop was the Red Rose Diner in Towanda — part museum and part grubfest. This 1927 diner was built by the P.J. Tierney company, whose innovation in pre-built diner manufacturing was to add such refined touches as stained glass and an indoor bathroom, an effort to double the restaurant’s customers by attracting women as well as the male regulars. There was even a special invitation (which remains, along with so many other original details) above the door: “Ladies Invited.”

With blackberry pie to go, we continued on toward our resting spot for the night.

The centerpiece of our trip was Wellsboro, a town that, without veering toward Pleasantville parody, is just as a town should be. We settled into the stately Penn Wells Hotel on the town’s sharp Main Street, lined with flickering gas lamps. It’s right next door to the art-deco Arcadia movie theater, which opened in 1921 to show silent movies and still features first-run films on four screens, and across the street from Dunham’s Department Store, an independent store that has been family-owned since 1905.

We would have liked to linger with the people strolling downtown that evening, but we had a date with darkness.

Cherry Springs State Park, an hour west of Wellsboro, is one of only a handful of places in the country that have been awarded a distinction for their dark skies by the International Dark-Sky Association, a group that works to preserve the night sky. The park’s combination of features, including an open field affording a 360-degree-sky view from atop a 2,300-foot-high mountain and a location far from population centers, gives Cherry Springs some of the darkest skies — and best stargazing — on the East Coast.

We attended one of the regularly held ranger-led programs as the sun set. (Ours was about lunar landings, since the moon was full that night.) By dusk, the wind was whipping through the tall pine trees ringing the open stargazing field. We sat mesmerized by a moonrise so bright in this dark dome of sky that it, like the sun, became too powerful to look at directly. So we took to the astronomy field and gazed into telescopes that the rangers had set up. My sons saw Saturn for the first time, the younger one fascinated by the word, the older one captivated by the planet’s rings.

The next morning our crew ate like lumberjacks at the classic Wellsboro Diner before hitting the road and heading into the woods. Past Wellsboro, Route 6 moves into wilder country as it dips in and out of state parks and national forests. The towns are less the social and commercial centers we’d seen the day before and more like outposts with canoe and snowmobile outfitters and log-cabiny restaurants.

Our morning stop was the Pine Creek Gorge, the so-called Grand Canyon of Pennsylvania. The visitors center at Leonard Harrison State Park has easily accessible walkways to overlooks of the 47-mile-long, 1,000-foot-deep chasm. Michael and I would have enjoyed the advanced hike to the bottom of the gorge, but with a little guy in a frame pack on each of our backs, we opted for the gentler rim trail.

Later that afternoon, after dancing at the end of the Kinzua Viaduct, we stopped at the extensive and charming Pennsylvania Lumber Museum. With its re-created logging camp on 160 acres, the museum offers the chance to explore the life of a wood hick, as the late-19th-century lumber workers were known, who logged white pine and hemlock.

That evening, we circled the cozy town of Kane and the more industrial Warren looking for lodging. There were gorgeous manor-home bed-and-breakfasts in both towns (the Kane Manor and the Horton House, respectively), and had it been just the two of us, we would have enjoyed staying at either. But we opted for a more kid-friendly chain hotel with a pool in Warren. (National franchises are pleasantly absent along much of the route, but available in the larger towns.)

What might have been

On our last day, we made the relatively short drive to an intersection called Union City, where we bade Route 6 farewell and headed 25 miles northwest to the shores of Lake Erie.

We made a beeline for the lake’s coastline, not stopping until we were in the parking lot of Beach 11 at Presque Isle State Park. The 3,200-acre peninsula that juts out into Lake Erie is Pennsylvania’s premier beachfront. With 12 guarded beaches and hiking and biking trails throughout the park, not to mention boat rentals, picnic shelters and playgrounds, there was plenty for us to do.

But the boys were keen to build sand castles. We all lay in the sun on the smooth sandy beach as the water gently moved in and out, tumbling into the boys’ rudimentary moats, causing squeals of elation. For a moment, we were all floating in contentment, having arrived at the end of our journey.

But what of Marie Antoinette?

Oh, she was there along Route 6.

Well, almost.

There’s a scenic overlook in Bradford County, high above a flat and fertile valley along the banks of the Susquehanna River. Now farmland, the valley was chosen in 1793 as the site of an asylum settlement for royalists fleeing the French Revolution — including, it was hoped, Marie Antoinette. But of course she never came — she was executed in October of that year — and the settlement disappeared. We stood in the overlook’s turrets on the hill, gazing at what was to be her refuge with the inescapable wonder of what might have been.

Then I turned around.

Before me stood a roadhouse tavern. Peeking inside, I saw a congenial scene around the bar. Outside was a simple sign: “Cold Beer. Hot Food. Bikers Welcome. Cabins for Rent.”

It may not have been Marie Antoinette’s cup of tea, but I’ll bet that Sal Paradise would kick himself for having missed it.

Bahney is a Washington writer.