RECREATION : GETAWAYS : Heading Off to the Passes : A mountain valley loop in Ventura County offers exhilarating descents and gradual, almost imperceptible climbs.

When searching for an ideal bicycle detour, look no further than neighboring Ventura County, favored for its flat, open country edged with mountains and rolling farmland.

This 27-mile mountain valley loop, half of it along a bike path and most of it with expansive views of the Sulphur and Black mountains, is prized for its exhilarating descents. After cycling through Foster Park, part of which parallels the Ventura River, you’ll pass through the town of Ojai, sharing the road with the town’s emerald green trolley cars.

Most of the uphill cycling is gradual and nearly imperceptible, so don’t worry about how you’ll earn the right to plunge down those mountain passes. Picnic tables with barbecue stations dot the park area should you consider a meal before or after your trek. Foster Park, open from dawn to dusk, charges a $1 entrance fee. Don’t forget your bicycle helmet.

The route begins along a 10-mile bike path called the Ojai Valley Trail, built in 1989. The Class 1 route is a designated off-road right of way for bicyclists, marked by wooden railings, that begins at the far end of the park’s parking lot.

You may spot red-tail hawks gliding just above hundreds of oak trees that pepper the surrounding hills along the paved route. Several covered rest stops are placed along the trail, some with great views of a valley that’s studded with yellow mounds of Scotch broom.

The surrounding 205-acre park is named for Eugene Preston Foster, considered the father of the Ventura County park system. Foster, who died in the early 1930s, was untiring in his efforts to persuade locals to deed their land to the county for park use.

The trail ends at Soule Golf Course in Ojai, where it intersects Ojai Avenue. Cross the street and head west on Ojai Avenue toward the center of town. In about half a mile at the southeast corner of Montgomery Street, you’ll spot some blue awnings fronting Antonio’s Mexican Food restaurant.

A street-side patio wreathed by red tile roofs seats 150. Or seek out the cool interior where Juan, a wooden, life-sized import from Guadalajara, sits, peering out a window. “He’s the only employee around who never talks back,” says owner Antonio Aguilera, who opened his restaurant 20 years ago.

The Mexican fare, under $10, is accompanied by Mario Santa Maria, who plays keyboard and sings Brazilian, Latin and South American tunes.

Saddle up and continue west along Ojai Avenue, where pottery and antique shops line the street.

In half a mile, you’ll come to Canada Street, where Ojai Avenue veers left. Continue straight ahead for two blocks as the street turns into Paseo Road. Turn right on Foothill Road, cycle one mile past estates fronted by stone walls to Fairview Road and take a left.

Miles of white rail fences stripe the hills before you. The narrow road dips and rises, then takes a one-mile spiral plunge through the hills. The view of Los Padres National Forest at the crest of the descent is stunning. Don’t forget to breathe--the scent of oranges and lemons mixed with eucalyptus is even headier than the view.

As you cross Maricopa Highway, take care--a blind curve to your left conceals oncoming speeding cars. You may want to cycle down the road a bit and find a safer place to cross. Continue straight ahead along Fairview Road for a quarter of a mile (don’t veer left onto La Luna Avenue) and turn left on Rice Road, where you’ll travel along a ridge with views of a valley strung with vineyards and orchards. Continue for two miles--all downhill--to Baldwin Road, also called California 150.

The busy road is unmarked, but look for the Frontier Paint store on your immediate right--and turn right onto Baldwin Road. Cycle for one mile, cross over the Ventura River and take a left on Burnham Road, following a curved descent along horse farms with such names as Oak Meadows, Rancho del Rey and God’s Little Acre.

In about two miles, Burnham Road will split to the left, turning into Santa Ana Road near a corner market. Continue on yet another downhill stretch for about three miles along golden hay fields. Turn left on Casitas Vista, which becomes Foster Park Drive, for a half-mile jaunt back to Foster Park.

After your trek, consider cycling or driving to Casitas Springs, one mile north from the park on California 33. The quaint town sports roadside fruit and vegetable stands, and folk art and antique shops.

Where and When Location: Ojai Valley Foster Park bike trail. Getting there: Head west on the Ventura Freeway toward Ventura County. Just past the city of Ventura, take California 33 north toward Ojai. Go about five miles to Casitas Vista Road exit and follow the signs, which loop you under the freeway to Foster Park entrance. Take a right into the driveway just before two stone entrance towers. Call: (805) 642-1591 for a free map of Ventura County bicycle routes.