The only sound in the crystalline mountain air was the crunch of our bicycle tires on the crushed limestone path. We’d pedaled around a bend, leaving behind the frothing Youghiogheny River and its whitewater rafters. Now, as we paused to split an orange, my husband and I looked down the path ahead of us, through the springtime trees just beginning to leaf out. The morning sun slanting between their narrow trunks striped the trail with parallel bars of light and shadow.

“Look,” Rick said suddenly. “What does that remind you of?” I saw what he meant, and laughed: “It’s the train tracks!”

The shadows formed a perfect echo of the long-abandoned railroad that once ran along this path, transporting coal and timber for western Pennsylvania’s thriving steel industry. Today, those tracks are gone, replaced by one of the finest achievements of the nation’s growing rail-trail network: the 141-mile Great Allegheny Passage, or GAP.

Details on biking the GAP and the C&O Canal

We were riding the passage from its western end in Pittsburgh down into Maryland. There we’d get on the venerableChesapeake & Ohio Canal towpath, which runs 184 miles more or less along the Potomac River, ending up in Georgetown. Together, and including the GAP’s Montour spur around Pittsburgh, the two trail systems offer more than 330 miles of hassle-free hiking and biking.

Last May, to celebrate my birthday, Rick and I bicycled about 300 of those miles. When I told our friends about our plans, some of them were, well, dubious. I know they pictured exhausting days, hard nights in grungy trailside cabins, cold showers or none at all. “Well, if that’s the kind of thing you like,” they said.

Well, here’s how it turned out: We cycled over the Allegheny Mountains and never broke a sweat. (Let me repeat: over mountains, no sweat.) At least 250 of our 300 miles were totally traffic-free. We saw goldfinches and mud turtles and peacocks, passed small towns and Civil War battlefields and countless waterfalls. We got pleasantly tired every day, and slept every night in comfortable, often charming, inns. We ate so well that Rick gained two pounds. And we wound up by pedaling (triumphantly) off the C&O and right into Bethesda for a family dinner.

Yep. That’s the kind of thing we like.

The C&O has been well known and beloved since 1971, when it was designated a national park after a campaign originally led by Supreme Court Justice William O. Douglas. The GAP, on the other hand, has been cobbled together piecemeal over 30 years out of various abandoned railway beds, with the help of seven trail organizations and dozens of federal, state, local and private agencies.

Two features make the GAP a pretty deluxe ride. First, its mostly crushed limestone surface is bike-friendly and fast-draining. Second, and more importantly, the trail’s railroad grade means that you’re never riding on a hill steeper than a train can climb. In other words, it usually feels almost flat. Though we gained 1,700 feet in elevation over the first three days of our ride, we kept wondering when we were going to actually start going up.

Instead of pedaling into and out of valleys, we glided over them on steel trestles — from the cast- and wrought-iron Bollman Bridge, an architectural artifact just a few dozen yards long, to the 1,908-foot-long Salisbury Viaduct, a modern span over the Casselman River valley. And instead of laboring over mountain peaks, we went through them — most memorably the 3,300-foot-long Big Savage Tunnel, just north of the Maryland-Pennsylvania border. Claustrophobes, take note: That’s a long way to pedal underground, even though the tunnel is lit.

(Even spookier is the C&O’s 3,118-foot Paw Paw Tunnel, where the path is not only unlit but runs alongside the murky waters of the canal. Puny bike lights hardly make a dent in the profound darkness, and even though there’s a railing, most people walk it. )

Given the part of the country you’re biking through — settled by Europeans hundreds of years ago, crisscrossed with roads and peppered with towns — you might expect to see more civilization. Instead, you usually feel separated from it, riding through what’s been described as a “green bubble” through overdeveloped America. Only a few miles off to the side, you might find freeways or strip malls; but all you actually see, for hours at a time, is serene, wooded countryside, rarely spectacular but often beautiful.

Every few miles along the GAP, it seemed, we’d pass another picturesque waterfall plummeting from rocky cliffs, or babbling around boulders, or cascading in sheets down ledges of shale. And then there was the Red Waterfall, near milepost 28, which takes its color from iron oxide and its poisonous character from sulfuric acid, both byproducts of decades of coal mining. Thousands of miles of streams in western Pennsylvania are devoid of life because of acid mine drainage. But progress has been made in cleaning them up, and the fact that a marker near the waterfall notes the historic damage and the EPA’s successes is, well, if not exactly cheering, basically a good thing. And it’s definitely pretty.

The mines’ legacy reflects a key characteristic of the Great Allegheny Passage: It runs near or through towns that sprang up in the heyday of coal mining, steel manufacturing and railroad transportation, the era of the Carnegies and the Mellons and the Fricks. Around the turn of the last century, the region featured not just thriving coal, coke, timber and mill towns, but also mountain resorts whose well-heeled guests arrived by convenient trains. That’s mostly gone today.

So the green bubble takes you through a region with lots of economic problems. Many of the towns are somewhat poignant: too many empty storefronts or bravely maintained houses, too many “antiques” shops. We happened to arrive in Cumberland, Md., on prom night, and the decked-out kids parading toward the dance made us feel a bit of wistful worry, a kind of “Last Picture Show” fear for what their futures would hold.

The upside of this is that most locals see the trail as a small but real economic engine; several innkeepers and business owners told us that they count on travelers like us for most of their business. Bicyclists and hikers are welcomed with enthusiasm. We arrived at Perryopolis — our first stop, about 35 miles southeast of Pittsburgh — after slogging through a couple of hours of dull gray rain. Mud-spattered, we seemed inappropriate guests for the Inn at Lenora’s, a meticulous Victorian bed-and-breakfast with an ambitious small restaurant.

But our gracious hostess welcomed us onto the broad front porch, brought out cookies and tea and a beer for my husband, and helped us hose down our bikes and equipment and stow everything away.

Other innkeepers offered laundry facilities or packed lunches. And several assured me that if weather had halted our trip, they were prepared to make accommodations — loading our bikes into a van and driving us to our next stop, or refunding deposits if we just couldn’t get there at all.

The high point of the trip, geographically and emotionally, came in Meyersdale, Pa. Technically, we were still a few feet below the Eastern Continental Divide (2,392 feet above sea level), which was eight miles away. But it’s close enough.

We’d paced our trip to give us a short ride on my birthday. So we arrived early at the Levi Deal Mansion, a B&B named for the coal and timber baron who built it in 1900. The house is only a few hundred feet off the trail, in an otherwise unremarkable neighborhood. But from the moment we stepped through its handsome double doors, we were in the Gilded Age. The afternoon sun glowed through stained-glass windows, beautifully restored hardwood moldings gleamed, and polished tables and shelves held interesting books and pictures. The ceilings were high, the rooms were spacious. There was nothing fussy or overwrought, no doilies or tassels — just quiet opulence and extreme comfort. Our oversize bathroom had a big whirlpool bath and a tiled walk-in shower. The top floor housed the old ballroom.

It didn’t hurt that my husband had told the innkeepers and our friends that it was my birthday, so I was greeted with a small avalanche of presents and good wishes. Our hosts offered us small sandwiches and homemade chocolate ice cream. We made some new friends — lured with gift bottles of champagne and beer that we couldn’t possibly carry on our bikes — and had a surprisingly tasty fried haddock dinner at the White House Restaurant, a 20-minute walk through the warm spring night.

Which reminds me: This could be a good ride any time of year, but I recommend May if you can manage it. In summer, the weather is pretty dependable and everything is open, but the trail is crowded. Autumn is stunning in the mountains, but by September the days are getting short.

In May, although some amenities still haven’t opened for the season, the trail has only a smattering of travelers and the sun doesn’t set until 8. The weather isn’t too hot, and because the trees haven’t fully leafed out, you can see much greater distances. It’s an airier ride.

Leaving Meyersdale, we spent our last day on the Great Allegheny segment of the ride. After a short (easy!) climb to the continental divide, we coasted most of the next 23 miles down to Cumberland, then followed signs through town — one of the few days where we encountered (horrors!) automobiles — to get to the head of the C&O towpath.

Much has been written about that trail, so all I’ll describe here is our favorite overnight stay: at the Buck Valley Ranch, which isn’t actually on the trail. It’s about 15 miles northwest of Hancock, Md., near Warfordsburg, Pa. But if you make a reservation, they’ll tell you to call from the trail and they’ll come get you in a well-used pickup equipped with a homemade rack for bicycles. Then they’ll drive you up winding mountain roads to the ranch — a good old Western-style guesthouse.

We’d stayed there once before, and I can’t overstate how down-home happy this place makes me. You’re fed a homemade supper with just the kind of meat and vegetables you grew up with, or should have. Beautiful horses graze within sight of the comfortable porch. A few peacocks strut around the property. There’s a hot tub out back if you need to soothe your sore muscles under the moonlit mountain sky, and you can help yourself to a beer, a glass of wine or a dish of ice cream.

Our fellow guests were a couple of wild turkey hunters; after dinner, one gave me a beautiful feather for my birthday. We ate breakfast alone, since they got up at 3 a.m. to do whatever it is hunters do before dawn. Having coffee on the porch at around 8, we saw our friend, swathed in the most amazing feather-bedecked full-body camouflage, sneaking across the far end of a field in silent, tense pursuit of a bird.

We kept quiet till he was out of sight. Then we got into the pickup and headed back to the trail.

If you want to ride the trail, begin by deciding how much you want to ride every day. My husband and I are lazy and like to sightsee, so we averaged 30 miles a day, which was never more than four or five hours of actual pedaling. A more common pace is 50 or 60 miles a day.

Then decide which direction you want to ride in. We went west to east, which sends you up a gentle slope to the continental divide, and a one-day glide down the other side before hitting the canal. If you start from Washington and go east to west, the canal portion is pretty similar (i.e. flat), but there will be one day on the Great Allegheny where you have to climb 1,800 feet in about 24 miles. It’s not a brutal climb (less than 2 percent grade, and in fact there’s a little railroad that will take you up that segment if you want), but it’s definitely harder.

Whichever direction you go, the Pittsburgh end is a little tricky. Unless you’re renting a bike right there, you have to get yourself and your bike to or from the trail, and no route is simple. We ended up renting an SUV one way, loading our bikes in the back and driving to a boring motel near an Avis location just south of Pittsburgh. Then, after returning our car in the morning, we called Bill’s Taxis (412-855-4484) and got shuttled out of the urban sprawl and onto the trail near Boston, Pa.

Three things left to say about this trip: First, you’d better like riding a bicycle — not as exercise, or as a challenge, but as a process. You’ll be pedaling hours a day, watching the landscape go by. Long stretches will be repetitive, almost meditative. It’s all green and natural and lovely, but it’s not dramatic. (I’m not saying that you can’t do some of this with an iPod and headphones, but then why not just stick to an exercise bike at Gold’s Gym?)

And you’d better like whoever is riding with you — especially if you ride before June or after August. There are many miles where the local population is just going to be you, the hawks overhead and a couple of turtles plopping into the canal. Love the one you’re with.

Finally, when I said it’s a no-sweat trip, I was serious. Did I mention that the birthday we were celebrating was my 60th?

Details on biking the GAP and the C&O Canal