hen my wife and I asked the mountain bike shop owner in Downieville, Calif., to recommend a long, moderately challenging ride, he traced his finger along a map. "You'll like this one," he said. "Bring a camera and some food. Take your time. Enjoy the scenery."

"Right," I thought. "Food and camera. Take our time." I figured he had us pegged as noodle-legged city dwellers and had steered us to what his state's governor might call a "girlie ride." Four hours later, I almost wished that had been true.

Somewhere up there, maybe around the next bend (but probably not), was the apex of the trail. Sweat rolled off my chin as my bike's knobby tires crawled over a hunk of granite. On a bright 75-degree day, Cathleen and I were ascending through the pines and cedars of Tahoe National Forest just outside Downieville, a 154-year-old Gold Rush town nestled in these brawny hills.

Our three days in this area -- about 75 miles northwest of Lake Tahoe -- were part of a nine-day sampler of outdoor frolicking and funky towns in the northern third of California, a chunk of U.S. territory harboring huge, awe-inspiring tracts of public land. We had started in Mendocino after flying into San Francisco, renting a car and pointing it north through rolling wine country. We wanted to immerse ourselves in California's sunny, green outdoors and still have access to indoor plumbing, cold beer and warm food.

Between the Mendocino coast and Downieville, our itinerary would take us to the Mount Shasta area, and would at least partially restore my hope that not everyone in this country is hellbent on the obsolescence of open space. Our route -- mostly on two-lane roads, from San Francisco to Mendocino, on to McCloud and down the spine of the Sierra Nevada to Downieville -- took us through big, muscular country, with huge tracts of forest, broad views of wild space, fields of flowers, sweeping coastline, snowy volcanoes and monstrous stands of redwoods.

Biking the Gold Trail

The Downieville bike ride started out innocently enough. We rode past a steakhouse, an antiques store and a museum fronted by Old West boardwalks, then through a neighborhood of small homes sporting U.S. flags. The road turned to dirt and we ducked into a rolling single-track trail through thick forest. Around one bend, at Paulie Creek, the earth dropped 70 feet to a series of pounding rapids. The trail was barely wider than our handlebars, prompting the same apprehension you might feel walking along a sidewalk seven stories off the ground.

"Wow," I said to Cathleen. "Hand me that camera."

The path jumped between trees and river bluff for a few miles before crossing a road and widening beneath towering cedars. At a curve in the creek, we climbed down the slope and kicked back on a big, flat rock to eat apples and dip our feet in the emerald water.

After the break, I was pushing ahead and thinking how fit I'd be if I did this ride every weekend when I heard a yelp. "Briley!" (My wife calls me that.) I raced back and found Cathleen sprawled on a slab of rock, facing downhill and tangled in her bike. "Wow," I said. "Hand me that camera." This remark was poorly received.

The trail led us past signs reading "Active Claim: No Prospecting" and through a gold mining camp with a cabin and what appeared to be mining gear scattered about. They don't find much gold here these days, but in 1850, Downieville was the epicenter of the Gold Rush. Prospectors pulled so much gold from the area -- including a 25-pound nugget -- that the town came just 10 votes shy of becoming California's capital.

Finally we crested the trail. The descent was worth every calorie of climbing: The grippy dirt held our tires through leaning turns, planes of sunlight diving through the trees. On the fast sections, the surrounding forest was a blur. The last slice of trail brought us around an exposed rocky shoulder with dry dirt more characteristic of a desert than a lush mountain, before funneling back into the canopy. When the trail finally spat us out at the top of town, we rolled, spent and dusty, to the Riverview Pizzeria for lunch under a blue sky.

Afterward, we followed the Yuba River a mile upstream to our cabin at the Lure Resort. Our A-frame sat upriver from all the others, affording an unobstructed view from our deck of the water and the steep hills beyond. Later, as dusk settled in, we cracked a couple of pale ales and listened to the concert of river, crickets and cicadas. I could have dozed right there on the deck, but then I remembered I'd seen a saloon adjacent to the bike shop. Ducking into the St. Charles Place, we found all the trappings you'd expect in a western bar: cold beer, stuffed mammal heads, twangy music and cantankerous locals.

The next morning, seeking more bodily abuse, I joined 10 other mountain bikers for the renowned Downieville Downhill, a 17-mile descent attained via van shuttle from town. We were dropped amid snowbanks at 7,100 feet (4,300 feet above Downieville). Most of my fellow cyclists were hard-bodied guys in their twenties and thirties, and a few of the younger ones were downhill specialists with motorcycle-style helmets, well-padded body suits and very serious looks. They sat low in their saddles -- a more stable position for keeping control at insane speeds -- and, immediately after leaving the van, vanished down the ridge to the trail head.

The route was stop-and-go through intermittent snow for a couple of miles, then dropped into a warmer zone. Launching over one knoll, I landed on the edge of a shallow creek and squeezed my brakes a little too urgently, earning me a free bath and a few minor raspberries on my legs. True to the marketing, the trail went down, down and down, leaving my hands sore from braking and my face sore from laughing out loud. After two hours of speed-freaking, I limped into town.

Fly-Fishing in McCloud

We had come to Downieville from McCloud, Calif., a tiny historic town in the shadow of Mount Shasta, a dormant 14,162-foot volcano and the second-highest peak in the Cascade Range. McCloud has a few things going for it -- a quaint main street with a handful of shops and inns, friendly residents and proximity to Shasta and the surrounding wilderness -- but extended operating hours is not the town's strong point.

We arrived at 9 p.m., well after every restaurant had blinked out. So instead of "May I take your order?" the clerk at Reginato's Mini Mart said, "They been sittin' there all day, so if you want 'em I won't even charge you," as she liberated two leathery chicken patties and fries from the heat lamp. One of us (ahem) had misjudged the driving time from Mendocino to McCloud. Someone had told me four hours; somehow it took us eight -- which was okay, since the drive through the hills of Shasta-Trinity National Forest was spectacular.

We awoke in the charming Victorian confines of the McCloud River Inn, the converted headquarters of the McCloud River Lumber Co., which dominated this town, 60 miles from the Oregon border, in the early 1900s. Our room's pine-slat ceiling still had a wooden frame from which company executives would pull down maps the firm used to track its operations.

The aroma of egg casserole led us to an airy second-floor dining room with a long table and high-back chairs. The guests fitted the region: Two of the three couples worked in forestry for various organizations (they weren't the most lively conversationalists, but I was comforted to know that people are protecting our public land) and one older man and his young date in town -- like us -- to fly-fish the McCloud River.

Local fishing guide Wayne Eng set high expectations: "If you want scenic beauty, you're coming to the best river in the country." Stepping through the brush after a 30-minute drive from town, I conceded that he might have a case. The river ran 50 feet across, the water rolling over a freestone bottom between banks of auburn fir, pine and alder trees that lifted gently into the surrounding hills.

Eng, a thin, mellow, 54-year-old Chinese American with a black ponytail, wore his reverence for the local environment proudly: He repeatedly referred to the nearby Sacramento River as "my river" and said he hadn't kept a fish in 20 years. "Oh, I'll go out to catch lunch for me and Myrna Rae [his partner of 21 years] and I'll get a nice trout, but think, 'Okay, I'll keep the next one.' Five or six fish later, I'm saying the same thing and it's time to go home."

We stood in the 50-degree water casting into the flow as dapples of sun fought through the clouds and lit up the river.

I enjoy fishing more for the beauty of the battleground than for the snaring of fish, but I expected the McCloud to produce. Renowned among California anglers for its robust wild rainbow trout, the McCloud holds distinction as the first U.S. river to export its stock. Pioneering anglers took fish eggs from here in 1874 and planted them in rivers around the country. Eventually McCloud trout eggs were shipped to streams in Argentina, New Zealand and the United Kingdom.

Shortly before lunch, we were fishing the upper McCloud, above the second of the river's three scenic waterfalls, when a fish nailed my fly. The reel whined as the trout took out line. He tired quickly and I led him -- a 12-inch wild rainbow with a brilliant pink flank and speckles on its back -- to Eng's waiting hands.

We drove an hour through foothills to the more remote lower McCloud, where the water runs wider. The road took us past McCloud Lake, with aqua hues courtesy of the glacial melt from Mount Shasta.

The lower McCloud is publicly accessible only through land owned by the Nature Conservancy and fishing is limited to 10 people at a time (the access tags, available on a first-come basis, hang on a board at the trail head). We took two tags and hiked a half-mile downriver.

Eng was helping me untangle a fly from a tree (don't ask) when Cathleen yelled. We turned to see her rod bent to the water as a radiant rainbow flashed above the river. The 14-inch fish leapt twice more, dancing on the river, before she brought it in.

Well-Protected Mendocino

The speed limit in Mendocino Village is 25 mph, but you won't want to go that fast. As I downshifted off of Highway 1, my first impulse was to get out and walk. The seaside village of gardened homes, weathered Victorian storefronts, cafes and inns sits on a gentle slope surrounded on three sides by rocky bluffs bridled with footpaths and wildflowers. Mendocino is a three-hour shot north of the Golden Gate Bridge, but it seems a continent away from the bustle of the Bay Area.

Mendocino Bay opens to the south, and behind it, lumpy coastal hills and the faint ribbon of the highway fade in the mist. Hippies, former and nouveau, amble the streets along with tourists who come here mostly for the slow pace (there is no cell phone reception), the phenomenal scenery and the offbeat smattering of stores and excellent restaurants. The bluffs are part of Headlands State Park, one of 12 protected areas within a 12-mile radius of Mendocino. We had put Mendocino on this itinerary almost exclusively due to these undeveloped playgrounds, and I saw us jumping from the car, lacing up our hiking boots and skipping into the wilderness.

But as we stepped out of the car at the Agate Cove Inn, a collection of quaint duplex cottages overlooking the ocean, with an explosively colorful flower garden and a bench under a big cypress tree, I thought, "Or we could sit here all day, drinking wine and counting waves."

The sedentary leisure, however, would wait. We headed to Russian Gulch State Park, one mile north, and jogged into the loamy hills. The rolling trail paralleled a creek, taking us past a 36-foot waterfall, through a canopy of massive redwoods and back down toward the coast. We ran and walked for an hour without seeing another person.

I was still thinking wine when we sat down to dinner on the enclosed wraparound porch of the MacCallum House Inn and Restaurant, an 1882 Victorian cottage fronting Mendocino Bay. But the nightly drink special -- organic cherry margaritas -- proved irresistible. I followed with king salmon over fettuccini, encored with another cherry marg and eavesdropped on a Willie Nelson look-alike, his biker-hot wife (of indeterminate age) and a twentysomething son who was howling with laughter disproportionate to the humor of the conversation.

The next morning, we lay in bed watching from our picture window as fog floated in off the gray Pacific. At breakfast, Russell and Sandra, a couple from Indianapolis, raved about a nearby gallery that sold woodcrafts made by local artists. Checking out its wares later -- $3,500 mahogany lamp stand, $10,000 dining room table, a pair of $2,000 (each!) rocking chairs -- I carefully backed out of the store with one thought: "Must learn Russell and Sandra's investment strategy."

The next morning, we headed just south of town to the Big River, which snakes out of the hills and into the ocean at a sandy beach on Mendocino Bay. We rented an outrigger canoe and headed upriver, past brackish marsh and through tens of thousands of acres of protected territory. An incoming tide aided us up the river's long, wide curves. Great blue heron fished the banks and an osprey screeched high overhead. After a few miles, the river narrowed and a pack of otters surfaced, one after the other, eyeing us shyly before ducking away.

Back in town, we ate Thai tofu burritos and drank Red Tail Ale, a local brew, at the Mendocino Cafe, melting into the town's narcotic rhythms. Given what has happened to so many other formerly idyllic American towns, I could almost sympathize with the clerk at Wild Thing, a small clothing store in the center of town. The friendly, fortyish woman in jeans and a paisley shirt took issue with the abalone divers who frequent Mendocino. "They're all fat, they park their trucks on the beach, leave their trash everywhere and go out diving alone when they don't even know the currents. One of those guys dies, like, every month. Completely obnoxious."

She was otherwise very pleasant, and the store was a hit: Cathleen bought a pair of bold red jeans and an Indian print sequined top, and I scored a stack of oxymoronic postcards (an African bushman reading Playboy, a kangaroo slugging a tourist).

We took our last Mendocino hike through a pygmy forest, where, due to the hardpan soil, most full-grown trees top out below shoulder height. A plaque told us that this terrace would eventually regain full fertility through erosion and new soil deposits. Lacking the time to wait for that geologic event, we hiked down into Van Damme State Park, where redwoods large enough to house hobbit families shadowed bright ferns.

After a few miles, the trail bottomed at a creek crossing before rising again into the hills beyond. As I would do later in Downieville, I wondered how far to the top of the trail. But for now, I was in no hurry to get there.

John Briley last wrote for Travel about the Outer Banks.

Northern California is like an outdoor theme park that never closes. You can hike around or fish in Sardine Lake (inset, left), near Sierra City and framed by the Sierra Buttes. Or take the Downieville Downhill, above, a 17-mile descent by mountain bike that starts in snowbanks at 7,100 feet. Fly-fishing guide Wayne Eng assists the author's wife on the McCloud River, near California's Mount Shasta and known for its wild rainbow trout. The Agate Cove Inn in Mendocino is a group of cottages overlooking the sea.