RIDGEPORT, Calif. — The heifers are acting surly, but my horse pushes forward. Ten or so cowpunchers encircle about 30 head of cattle on a wide pasture in the shadow of a sawtooth mountain just west of Bridgeport. Our horses slowly lead the cattle toward a gate at the far end of the field.

"Move on," I yell, as I nudge my mount with the heel of my boot. "Heeeaaah!"

For a moment, I think I'm a cow-herding, range-riding, genuine cowboy.

Who am I fooling? I'm just a part-time pretender playing cowboy at a dude ranch only a few miles from a 24-hour convenience store, a corner deli and a big-box retailer. I've donned a pair of old boots and mounted a swayback horse because I think I have the grit and guts to cut it as a cowboy.

At least, that's what I thought.

My grandfather Alejandro was a real cowboy. He had leathery brown hands, a frozen squint and a faded black cowboy hat perched on his head. Back in Mexico, he milked cows, slopped pigs and rode a horse into town for supplies.

Two generations later, I'm a fully integrated city-dweller, with soft, office-worker hands, iPod buds in my ears and a cell phone clipped to my belt.

So I was thrilled at the idea of a week at a working cattle ranch, where I was sure my deep-rooted "vaquero" instincts would emerge.

But dude ranches today are more like resorts. Even the ranch depicted in Billy Crystal's 1991 comedy, "City Slickers," looks grueling by today's standards. Liability fears and tough competition from resorts and cruise lines have forced dude ranchers to adjust, according to the folks at the Dude Ranchers' Association, an alliance of more than 100 guest ranches in the Western U.S. and Canada.

That means no cattle branding or horseshoeing. Instead, visitors enjoy swimming pools, hot tubs, saunas and tennis courts.

Grandpa, I am sure, is spinning in his grave.

THE REAL DEAL

My search for an authentic cowboy experience leads me to the Hunewill Guest Ranch, on the outskirts of Bridgeport, about 360 miles north of Los Angeles. The 4,500-acre working ranch sits in a wide, flat valley between Yosemite National Park and Bridgeport. More than 190 horses and about 2,400 head of cattle call the sage-studded valley home. The Dude Ranchers' Association tells me this is one of the few places that has resisted the resort trend.

In the early 1800s, Napoleon Bonaparte Hunewill struck out from Maine, hoping to make a fortune in gold and timber. He homesteaded and founded the Hunewill ranch in 1861. In the wake of the Great Depression, his descendants opened the ranch to guests. Today, Hunewill's great-great-grandchildren run the business.

On paper, the place sounds authentic. But during my weeklong stay in June, I learn that even Napoleon's offspring have had to adjust to modern times. And I realize I don't mind at all.

BACK TO BASICS

"Grayson!"

"Tyson!"

"Tequila!"

"Elmo!"

The wranglers holler out the horses' names, each of which has been assigned to a visitor for the week. About 50 guests — nearly half are younger than 14 — wait at the edge of the lot to hear their horses' names. Mine is Murphy, a muscular bay with a sagging spine and big, soulful eyes.

Mornings begin this way: After breakfast, we assemble for a horse roll call and then ride into the fields. The wranglers separate us into three groups based on riding skills. I'm relegated to the buckaroos, a euphemism for greenhorns.

Each day, we work on our riding skills, learning to turn, stop and keep our butts in the saddle. But by the end of the week, I'm racing across open fields, leaping over ditches, squealing like a kid, my horse's mane flying in the wind.

During breaks, we sit high in our saddles and listen as our wranglers recite a verse or two of cowboy poetry. Most of our wranglers are grizzled cowboys, sporting dusty spurs and CD-size belt buckles. So it's strange and somewhat sweet to hear such sentimentality from these leathery ranch hands.

Still, the spirit of Tom Mix and Roy Rogers has yet to take hold of me. One night, as the sun sets behind the Sierra Nevada, I drain a beer on the porch of my cabin. Sharing the porch is Bruce Forsythe, a retired dentist from Sebastopol, Calif. He sips red wine, and we chat about fishing, writing and family life. His parents first brought him to the ranch in the 1960s, and now he returns each year with his daughter, Samantha, now 14.

He says he likes that the ranch's guests are not distracted by modern electronics. The simple but comfortable cabins resemble ultra-economy hotel rooms: no TVs or phones, no minibars or coffee makers. For a touch of kitsch, the room includes a hat rack made of welded horseshoes. Don't expect high-end cuisine at the dining hall. The menu boasts mom-and-pop-diner meals — burgers, steaks and pasta.

Each night after dinner, the guests roast marshmallows around a campfire while our wranglers play guitars and sing country tunes. Another night, we try to milk a cow. The next night, we jump on a horse-drawn hay wagon for a ramble. One evening, the kids — and a few adults — put on a talent show, with skits, magic tricks and more sentimental cowboy poetry.

Later in the week, I meet Betsy Hunewill Elliott, the great-great-granddaughter of the ranch founder. She's the ranch boss now. The Hunewills have added a full-time masseuse and, beginning this year, Wi-Fi access. But she is leery about changing the character of the ranch, which has been in her family for nearly 150 years.

Of modernizing, she says, "We are torn."

MOVIN' AND AMBLIN'

Real cowboy work comes on my third day at the ranch when the wranglers ask guests to help move cattle from various pastures. In the field, about 10 of us form a moving column, slowly tightening our circle around a herd of brown-and-white heifers. Without prodding, our horses close in on the cattle. A few heifers briefly rebel, refusing to yield until they come nose to nose with our advancing column.

Next our crew circles a group of Angus steers. These fierce-looking beasts — the pit bulls of bovines — are tall and thick in the shoulder, but they offer little resistance as our horses approach.

Three hours of cowpunching and I ride back to the barn, thinking I might have what it takes to be a real cowboy. But reality sinks in when I get off my horse and waddle to my cabin to relieve my sore muscles with some ibuprofen and a chilled pale ale.

Toward the end of the week, I tackle another cowboy tradition: ambling. The wranglers move our horses by trailer to a lakeside campground about five miles east of the ranch. About 20 of us would-be cowboys follow in cars. We pack sandwiches and water bottles in our saddlebags and ride into the Sierra wilderness.

A dirt and rock trail leads us to Barney Lake, a deep blue mountain pool that was first stocked with cutthroat trout by Napoleon's son Frank Hunewill in the late 1800s.

The four-mile, single-track path follows the banks of a shallow, fast-moving creek. We are shaded by ponderosa and Jeffrey pine, white cedar and quaking aspen. Yellow mule's ear blooms and purple lupine adorn our path.

The sound of hoofs and the splashing creek fill the warm mountain air. When the lake comes into view between the pines, even our thick-skinned wranglers can't help but be stunned. "What a sight," says one. "Beautiful."

HANGING UP SPURS

By my final day, I've spent nearly a week in a saddle, and abandoned the title of "buckaroo." Maybe I'm not a cowboy yet, but I'm certainly no tenderfoot — witness Murphy and I as we sprint across the fields, leaping over narrow waterways.

Back at the ranch house that afternoon, the wranglers call for volunteers to move more cattle out of a pasture in the western end of the ranch. Nope, I say. I have an hourlong deep-tissue massage scheduled with the ranch's in-house masseurs.

Sorry, Grandpa.