SUMMERTIME : Life’s a Picnic : Nearby parks and mountains provide lush places for family getaways.

The days are long, the weather is warm and you have the afternoon off. Wouldn’t you like to in vigorate your senses, relax your mind and get some healthy exercise all at once? Wouldn’t it be great to show off a place so pretty that your out-of-town guests won’t believe it’s Los Angeles? Wouldn’t it be nice to spend the day with your family without spending any money?

The San Fernando Valley is better known for freeway traffic, shopping malls and Universal Studios than for wide open spaces. But you don’t have to stray far from home to find an oasis from civilization, perfect for picnics, hikes and leisurely strolls.

Malibu Creek State Park

Malibu Creek State Park, known as the gem of the Santa Monica Mountains, is a former movie ranch for 20th Century-Fox Films. Today, the 6,000-acre park, crisscrossed by more than 30 miles of rugged trails and fire roads, is a favorite of hikers, bikers and horseback riders.

The rock pool is one of the most scenic spots in the park. The quiet body of water, surrounded by rocky outcrops and sycamore trees, is just two-tenths of a mile past the visitors center, but you will have to scramble along rocks and boulders to get there.

You will also want to take the short and easy wildflower-lined walk to Century Lake. This hidden seven-acre lake was created in 1901 by members of the exclusive Crags Country Club, long since defunct. The lake, which is slowly filling with silt, has become a shady and peaceful freshwater marsh, patrolled by ducks and deep-throated frogs.

Docents discuss the history and ecology of Malibu Creek State Park on regularly scheduled walks. Try an evening campfire hike, followed by camaraderie around a campfire, at 6:30 p.m. Saturday and July 18. There is no charge for this easy two-hour walk.

Getting there: From the Ventura Freeway, exit on Las Virgenes Road in Calabasas and head south. The entrance is just past Mulholland Highway. Parking is $5.

Information: (818) 706-1310 or (800) 533-PARK.

Castaic Lake

Too hot to hike? Go jump in a lake. Castaic Lake, Southern California’s largest freshwater body of water, is just minutes north of the Valley. It’s an inviting spot to swim, fish or relax. If you’re feeling adventurous, you can take windsurfing and water-skiing lessons. Boat rentals are also available.

The 8,000-acre Castaic Lake recreation area refers to two separate bodies of water: Castaic Reservoir and Castaic Lagoon. The V-shaped Castaic Reservoir is the main lake, with 30 miles of shoreline and a surface of more than 2,200 acres, which can accommodate 500 boats and 75 jet skis. Its east arm is open to sailing, fishing and slow boating; the west arm is reserved for water-skiers, jet skiers and fast boating.

Castaic Lagoon, south of Castaic Dam, has three miles of shoreline. With sandy beaches, grassy areas and playgrounds, this area is perfect for picnics, swimming, sailing and canoeing.

Castaic Lake is usually full to capacity before noon on summer weekends and even earlier on the Fourth of July and Labor Day holidays.

To get acquainted with the lake, make the visitors center your first stop. The story of the California Aqueduct system is told through a variety of exhibits. Also on display are prehistoric tools and artifacts used by the area’s original inhabitants, the Tatavian Indians.

Getting there: Take the San Diego Freeway north until it merges with the Golden State Freeway, exit on Lake Hughes Road. Parking is $5, or $1 per person for walk-ins.

Information: (805) 257-4050.

Los Encinos State Historic Park

If you have only an hour or so to spare, visit Los Encinos State Historic Park, one of the original Indian settlements in the Valley. Even though the five-acre park borders Ventura Boulevard, it is peaceful and relaxing, perfect for a quiet rest stop.

In 1769, a group of Spanish explorers, led by Don Gaspar de Portola, stopped at the area. They were attracted by the warm freshwater springs that continue to flow. Today’s visitors can picnic under ancient oaks and olive trees, feed ducks and geese gliding along Encino Lake, or take a walk through buildings from Old California days.

Pepper, olive and pomegranate trees, and orange groves and grapevines, planted by Spaniards some 200 years ago, continue to thrive in the park, alongside a variety of native plants and trees, such as oaks, cactus, California lilac and California holly.

The park grounds are dotted with turn-of-the century farm implements, as well as several limestone buildings constructed during the 1800s, and a blacksmith shop crammed with antique tools and equipment.

The most impressive structure is the well-preserved 1849 adobe ranch house, luxuriously decorated with period furnishings. The two-foot-thick walls of the eight-room home are made of mud and straw sun-baked bricks. Tours of the interior are conducted from 1 to 4 p.m. Wednesdays through Sundays. Cost is $2 adults; children under 6 get in free.

A brochure describing a self-guiding tour of the park is available for 25 cents.

Getting there: From the Ventura Freeway, exit south on Balboa Boulevard. Turn left at Moorpark Street in Encino. The park is on the right at 16756 Moorpark St. Closed Mondays and Tuesdays.

Information: (818) 784-4849 or (800) 533-PARK.

Cross Mountain Park

Wilacre Park, Fryman Overlook, Coldwater Canyon Park and Franklin Canyon Ranch are linked by the Betty P. Dearing Mountain Trail. Together, the area comprises Cross Mountain Park. The area is worth a visit for its panoramic vistas, challenging hikes and educational displays for children.

Families with children will want to stop at TreePeople headquarters at Coldwater Canyon Park in Studio City. The environmental organization features displays and exhibits focusing on recycling, tree planting and ecological awareness. Also on the site are fruit and nut orchards, and flower and organic vegetable gardens. A retail tree nursery is open from noon to 5 p.m. weekends. Free guided tours are available Sundays by reservation.

Everyone will enjoy the short, pleasant walk through TreePeople’s Magic Forest Nature Trail. With picnic tables scattered under the trees along the trail, you will find plenty of perfect places to take a lunch break.

A brochure geared to children describes the plants and features of the TreePeople grounds and the nature walk. It is available for 25 cents.

After exploring the TreePeople site, energetic hikers will want to set out on the trail network linking the parks.

Getting there: From the Ventura Freeway, exit on Coldwater Canyon and head south. TreePeople is on the east side of the intersection of Mulholland Drive and Coldwater Canyon Avenue.

Information: (818) 753-4600. Tour reservations: (818) 753-4611.

Paramount Ranch

At Paramount Ranch in Agoura, it’s easy to imagine that you have been transported to the rough and ready old West. The picturesque Main Street is lined with a livery stable, gunsmith, mercantile and other weathered buildings with fading, chipped paint. The town is surrounded by rolling green hills, a horsy scent wafts through the air, and a creek gurgles through town all year.

But if you are counting on meeting up with Sheriff Matt Dillon, well, sorry. The authentic-looking buildings are facades, relics from the years when Paramount Studios owned the property, and hundreds of movies and TV Westerns were filmed here.

A park ranger will lead a free one-hour tour of the Western movie set and talk about Paramount Ranch’s show biz past at 9:30 a.m. July 18.

If you miss the tour, try the short, self-guiding Coyote Canyon nature trail. You will cross Medea Creek, mosey along the Western town and pass through shady oak groves.

Getting there: From the Ventura Freeway, exit on Kanan Road and head south for three quarters of a mile. Turn left at Cornell Road and continue 2 1/2 miles. The park entrance is on the right.

Information: (818) 597-9192 or (80) 533-PARK.