My son Matt, now a college junior, still remembers the moment at 8 years old when he first saw his stepdad, David, differently. "We took Josh {the springer spaniel} in the lake. He loved it. It was the first time he went swimming," says Matt. "I remember the three of us spent the whole afternoon playing catch with the dog, throwing the ball in the lake and watching him swim, and joking around. It made me feel closer to David."

We had rented a cabin at Mountain Lake Hotel in Virginia for our first blended-family vacation. We fled the city heat for some mountain coolness and lacy woods. But along with new-found skills in hiking and fishing, we came back with a significant dent chiseled in the blended-family armor.

For blended families -- those which contain children from a spouse's previous marriage -- the first lurch toward civility, let alone closeness, comes as the hardest. Conflicting loyalties and vague roles make "blending" seem like lumpy, karmic stew. At the time, Matt tossed icy remarks as swiftly as he kicked balls for his third-grade soccer team. David ricocheted from rules to explanations to exasperation, and I bounced in the middle as if caught on a hellish electrified barbed-wire fence.

So what we brought back from Virginia's woods sounded sweeter than any country dulcimer lilting through the pine groves in the moonlight. This vacation, like the many to follow, drew us closer.

Such experiences are typical. Vacations serve as powerful bonding times for any family, but especially so for blended families. Says Chicago-area psychologist and family therapist Seymour Schneider: "Vacations are an especially good time for the kids to get to know the stepparent, and to get to know them in a setting outside the house. Here they can go bowling and fishing and have an opportunity to connect in a much more playful way than at home."

For one client of Schneider's, a family with two adolescent sons from the mother's first marriage, a trip to Orlando was the beginning of better times. "One day the mother decided to go to a spa, so the husband took the boys to Sea World. They bought hot dogs, looked at Shamu, and had a wonderful time. With mother out of the picture, the kids could not run to her every time anything happened. The three of them worked it out. Thereafter, everything wasn't perfect, but the kids began to see their stepdad in a different light. He seemed nice and kind."

One reason: vacations mean time together without daily distractions -- homework, phone calls, meetings and business deals. Whether it's by the light of the campfire, in the shade of a palm tree-lined beach, or in the glow of candles on a rocker-lined cabin porch, vacation days allow family members to see each other with fresh, less defensive, and more forgiving eyes.

But while such pluses are much to be wished for, beware of -- and prepared for -- their sometime concomitant negativity. New bonds, especially in a blended family, may breed their own dragons. "The closeness may be threatening," notes Janet Laubgross, a Fairfax psychologist. "The parents may not be used to the intensity, therefore there's a little blowup just to create distance. One of the ways people pull apart is by arguing, especially for children and teenagers. In a blended family, because the relationships tend to feel more tenuous, it makes it more scary to be close because it's unclear what their roles should be."

Just after a laugh-filled afternoon hike and picnic, the kids may spend the return walk to the car grousing about the stupidity of vacationing in a place that doesn't have television. Such picking and pouting may be engendered by the children's need to slay their rising feelings of disloyalty.

Notes Laubgross, "If the kids are getting closer to a stepparent, then the kids might feel some disloyalty to their biological parent, and feel the need for some friction."

Family members, however, often remain unaware of this psychic dance. Children yell instead about a stepmother's bossiness when she insists kids pick up milk at the grocery, or complain about the "grossness" of another night in a rustic cabin far away from pizza. Parents foam with "After a whole day at the lake, he shouts at me because I spend five minutes with the newspaper?"

Even though your vacation balloon inevitably will pop with a few family fights, don't be dismayed. "Even while families make progress in closeness, they get into arguments because this is a time of transition," says Laubgross. "In general, it's two steps forward and one step back."

Some rules to vacation by, according to Laubgross:

"Stay as rational as possible. Don't take arguments personally. If a kid is creating a fight, he may not be mad at you but confused about his loyalties."

"Don't react when someone is screaming at you. Even if you have to walk away, say you'll talk about the situation later."

"Give the kids an option of addressing a specific issue, but don't do psychotherapy on a family vacation." If your stepdaughter seesaws between easy conversation with you and nasty barbs, then try to use an opening to get her to talk about her feelings. "Use your experiences, something like 'I had a stepmother, and when I got close to my stepmother I felt bad about my mother,' " as a lead in. "Realize, though, that the stepchild may not be ready to discuss her feelings, and don't push."

Despite the arguments, and in spite of the configurations of families, vacations remain a powerful force. Notes Laubgross, "The memories are real valuable. It gives parents pleasant things to remember about the family unit. This helps them face a lot of the tough issues that blended families face."

Memories also help anchor families by reinforcing bonding. "As much as possible," says family therapist Schneider, "we want to keep the bonding. When kids remember the times at the lake they used to bury dad in the sand, and the times mom would scale the fish, these help pull the family together."

So when Matt irritates me with a 2 a.m. phone call for directions I gave him the day before, or when my daughter shouts "Leave me alone," when I insist she clean up her room, or when they both argue about whether to watch Mr. Wizard or baseball on television, I pull out the memories.

After all, we'll always have Hawaii, and Vermont, and Phoenix and Wintergreen. ... And we'll get through.