Every year Marion Goertz, a registered marriage and family therapist in Toronto, takes to the open road with her sister and female cousins. The differences between their personalities are immense: one is completing her PhD in social work; another is a mom and teacher; and one is into making her own soaps and lotions and travels throughout Asia on medical education exchanges.

Sounds like a vacation nightmare waiting to explode, but because Goertz and her travel partners strike a balance between group activities and time apart, they have a blast every time. If travelling with family and friends appeals to you, the following considerations will help smooth the ride.

1. Decide if inviting friends and family is the best decision for everyone
Don't forfeit your child's happiness by inviting a family with children he doesn't get along with; it's his vacation, too. If your sister's constant chatter gets on your nerves when you invite her over for dinner, chances are you won't want her in the back of your car on a cross-country road trip, either.

2. Discuss what your communal trip would look like
Is every night movie night? Are you playing board games or computer games? Do you get up early or stay up late? Is the sight of someone checking work e-mail from a laptop welcomed or discouraged?

3. If you decide to go ahead, sit down before the trip and work out a plan together
Goertz suggests recruiting the logical list-makers of the group -- you know, the ones who always plan the best birthday parties or have all their spices lined up alphabetically -- to come up with a project-management plan, starting with research. If a canoe trip suits your desires, for example, research campsites, costs, necessary equipment, portages and trails, and skills required.

4. Once you have "what" figured out, work out the who, where, when, how (transportation, finances, logistics) and why
"Choose a time to sit down as a group or canvas all adult participants to remind yourselves what principles, such as strengthening relationships and sharing experiences, are guiding this effort," says Goertz. To stay focused on these principles, carry the list with you and refer to it often when things get tense along the way.

5. The planning team outlines an action plan that is a blueprint of the trip: timetables, maps and directions, who does what, reservations, contact information, etc
"It's absolutely vital to lay down ground rules," says Goertz. It's at this point that everyone needs to raise any questions and concerns. This is the time to share if there is a museum or roadside hot spot you want to visit that is missing from the schedule or if you just don't think the kids can last for eight hours in the car. "It's fair to speak up for what we want in the planning stages; it isn't fair to whine en route," says Goertz.

6. Be fair with finances, too
Each person can purchase his or her own groceries, but if you are renting a cottage together, divide the cost of food and liquid sunshine equally. If one traveller or family suddenly opts out of a preplanned day trip or event, they should cover any cancellation or nonrefundable fees. Outline ahead of time how finances will be divided and make sure everyone involved is comfortable with the final price tag of your vacation.