A FINE SPRING DAY will do it to us every time. I start longing for afternoons spent hunched over handlebars and my wife gets nervous, like she is now. When I got married, the first thing I bought my wife was a bicycle. When my daughter was born, the first thing I bought was a child carrier for the back of my bike. When she was approaching her sixth birthday, we went out and had her fitted for one of those small pink Kent beginner truck bikes with pedal brakes and a little basket in front for her doll. I bike to work. I bike my son to and from school. And when it's 60 degrees and the clouds are high and thin, I'm ready to take the kids and bike all afternoon.

But if there's one thing we've learned from past expeditions, it's that a family bike hike has to be planned. So we usually set a date a week in advane and then pray that it doesn't rain.

That week gives us time to: 1) check over the bikes; 2) pick a route that we hope will be comfortable; 3) plan some sort of activity for the times when we're not on the bikes; 4) stop at the grocery store; and 5) make sure that the kids get enough rest.

My wife's 26-inch purple Concorde gets the most attention during the checkups because it gets such little use. Then it's on to the other bikes, filling tires with air and readjusting hand brakes.

Although we have a couple of favorite places to ride, it's always more exciting to try a new route. And that's why my wife gets nervous. Our seven-year-old daughter has mastered our cul-de-sac, but she's still basically a novice, and many area bicycle paths run uncomfortably close to street traffic. Also, biking (and jogging) are so popular around here that many paths are often crowded with two-way traffic that can make maneuvering tricky.

And then there's our four-year-old son to deal with. He loves riding on the bak of my bike -- it's a source of pride when he arrives at school on my red 27-inch General -- but he eventually gets tired of sitting down. So we always plan stops, for lunch and to let the kids play ball or feed the ducks or fly a kite.

With all that, there are still times when the untested route works out just right -- as it did for us on a recent Sunday. We packed a lunch bag (sandwiches, fruit and paper boxes of juice that were frozen the previous night) and an accessory bag (tire repair kit, tools, bandaids, paper towels, pre-moistened towelettes), put the bike rack and bikes on top of the car and were out of the house by 10:30, bound for the George Washington Memorial Parkway trail to Mount Vernon.

After setting up base camp in the small parking lot at Lady Bird Johnson Park (just north of the 14th Street bridge)and getting the kids into their helmets, we followed the river south, with my ever-anxious mate bringing up the rear as guardian angel.

At the north end of National Airport we took a break with a treat for the kids -- watching the planes take off -- before continuing the trip south. Of course, some of my wife's misgivings found merit when the path crossed airport traffic or ran too close to the parkway, and we noted not to use certain sections of the route again until the kids get bigger.

But after we got to the Alexandria marina, ate lunch, watched the boats slip in and out and played tagging-up (a New York City street game played with a rubber ball and patterned after baseball's attempt to score from third base on a fly out), the mother of my children was ready, in fact insisted that we go a little farther south before heading back to the car.

My kind of day.

And apparently it had some appeal for her, too.

She just made the kids (all three of us) happy by agreeing to go on another bike hike this weekend. Now if it just doesn't rain. FAMILY PLANNING

Here are some options for family outings that avoid crowded paths or busy roads:

ROCK CREEK PARK -- It's heaven for a biking family, particularly in the car- less section (portions of Beach Drive which are closed to cars on Sunday year- round, and on Saturdays starting this weekend and running through November 11.). You can begin along the Potomac, across the parkway from the Watergate, then leisurely wind your way past P Street Beach, the National Zoo, the Art Barn at Pierce Mill and the Nature Center en route to the Recreation Center just across the District line in Montgomery County. And the best thing about this ride is that it's mostly flat.

NATIONAL ARBORETUM -- Enter at 3501 New York Avenue NE or approachable from Bladensburg Road at 24th and R Streets NE. It has little traffic (only student drivers and pleasure cruisers), and the speed limit is 15 mph. The hills can be tiring, but the abundance of flowers (especially in the spring) and the appreciation the pond's ducks show their feeders make for an enjoyable day.

FORT DUPONT PARK -- Just off Minnesota Avenue at Randle Circle SE. It's better suited for hiking than biking -- the road through the upper picnic groves is so steep in some places that walking is almost unavoidable. But there is a mile-long path with a gradual grade that runs by the amphitheater, and on Friday and Saturday afternoons during the summer, this path is used by cyclists waiting for evening concerts.

ANACOSTIA PARK -- 1900 Anacostia Avenue SE. It can be reached from the South Capitol Street Bridge at Howard Road, Good Hope Road or Nicholson Street (off Fairlawn Drive near Sousa Bridge on Pennsylvania Avenue). Although there is no bike path and the speed limit along the main road, Fairlawn Drive, is 25 mph, this a is party park and drivers are extremely courteous. The road, which passes a playground, swimming pool and the D.C. tree nursery, runs along the Anacostia River, so you might want to bring a fishing pole.

BURKE LAKE -- 7315 Ox Road, Fairfax Station. It offers an ideal setting -- a 218-acre lake ringed by a five-mile bike path, a mini-train for riding, carousel, golf and Frisbee golf, rowboats and camp grounds.