Over the river and through the woods...but wait — look at that check-in line! With some 20 million travelers flying Thanksgiving week (and even more taking off at Christmastime), planes are packed and the sky's the limit for ticket prices. The highways are busy, too. According to the American Automobile Association (AAA), in 2002 nearly 36 million people hit the road over the long Thanksgiving weekend. It's almost enough to make you want to stay home. But holiday travel doesn't have to be costly or even all that inconvenient. The following tips can save you time, money, and stress, whether you go by plane, train, or automobile.

THE COMPACT CARRY-ALL

In the air, on the rails, or on the road, a well-equipped bag (especially valuable on long flights) will help you relax.

hydrate: To prevent dehydration when flying, drink at least eight ounces of water every hour. Don't count on the airline having enough of the bottled stuff to go around. And some travel authorities question the quality of water from the airplane's tank.
keep it accessible: Choose an easy-to-open tote that gives you fast access to things you'll need during the trip.
fight boredom: Pack quiet activities, like crayons, activity books, or a Game Boy (with spare batteries and the sound turned off), to distract the kids. And don't forget a book or magazines for yourself.
cover up: Pack a shawl or a light sweater to stay comfortable no matter what the temperature. (The average temperature in an airplane cabin is 75 degrees.)
identify: Label bags with your name and your business, not home, contact information. Thieves troll airports looking for the addresses of people leaving town.
pack a snack: Airlines have eliminated food service on many flights — perhaps not such a bad idea. Fruit, granola bars, and sandwiches aren't too messy or smelly, and don't require knives.

BY CAR

Get good directions — in advance. On-line directions from sites like www.mapquest.com, maps.yahoo.com, and mappoint.msn.com are free to all. AAA members (who pay a $55 annual fee) can obtain free customized directions (plus real-time traffic reports in some areas) through www.aaa.com. With both AAA and Mapquest, you can get information on monuments, museums, and other attractions along your route, and choose roads that avoid tolls and ferries; Mappoint provides fastest- and shortest-route options. Print the directions in a large font so your copilot can read them easily.

For many people, the Thanksgiving holiday is the first long trip of the cold-weather season. Make sure your car is ready. Check coolant levels. Inflate tires to the level recommended in your owner's manual, not the maximum pressure shown on the tire.

Senior year, you and a case of Jolt Cola drove nonstop from Boston to Miami in 24 hours. But now it's time to embrace your inner minivan. Take a rest stop about every two hours and limit yourself to an eight-hour driving day so you remain alert. Even professional drivers (that is, truckers) are forbidden by law from driving more than eight hours without a three-hour rest.

Keep your passengers happy. If you have a backseat full of kids, a road movie could be the perfect distraction. You can rent portable, easy-to-mount VHS and DVD units from www.drivinsane.com (starting at $49 for four days).

BY TRAIN

According to Amtrak, last Thanksgiving more than half a million passengers rode its trains to holiday destinations. If you must travel on peak days, look for morning trains, which tend to be less crowded than those running later in the day (except on Thanksgiving Day).

Don't expect business as usual. During Thanksgiving week, most trains are "reserved," meaning you're guaranteed a seat on a specific train. If you have already bought an "unreserved" ticket, it won't work during the holidays.

Look for "passenger extra" trains. To bolster service during the holidays, Amtrak borrows commuter trains from local services (indicated on timetables as "passenger extra"). These trains tend to be less crowded. But if you're traveling longer distances, be aware that they may have fewer amenities than Amtrak's regular trains.

Stay up-to-date. Click on the "Check Train Status" button on Amtrak's homepage (www.amtrak.com) to learn about delays or service changes.

Use automated Amtrak Quik-Trak kiosks, available at all major stations, to print out your tickets. All you need is a credit or debit card and your reservation number.

BY PLANE

Book early. You've heard it before, but with many airlines flying up to 9 percent fewer planes than last year, it's more important than ever to make your reservations at least 21 days in advance for the best fares and availability.

Travel on off-peak days. The day before Thanksgiving is one of the busiest air-travel days of the year. On Thanksgiving Day, though, you have a good chance of getting a row to yourself, with planes flying only 50 percent full on average.

Choose secondary airports. To find fewer crowds and, often, cheaper fares, consider using airports like Chicago Midway, Oakland, and Baltimore/Washington instead of their larger counterparts.

Be seat-smart. The right seat can make the difference between a pleasant flight and an agonizing ordeal. Go to www.seatguru.com to find the most (and least) comfortable seats on a variety of airlines. For example, bulkhead seats (at the front of the cabin, where there's no seat in front of you) are great for kick-happy kids, and exit rows are usually roomy.

Lighten up. Ship gifts in advance (if you don't, they may be unwrapped at security checkpoints). If you have small children, you can rent cribs, strollers, car seats, and more through www.babysaway.com and have them personally delivered by local operators to destinations in 20 states.

If you book through www.orbitz.com, you can sign up for Traveler Care Alerts — sent via phone, e-mail, pager, or fax. You'll be notified about delays, cancellations, and weather or other local events that may affect your trip. Add contact information for friends or relatives and they'll get the updates, too. (Some airlines offer similar notification services. Check their websites for details.) Use the self-service kiosks at about 150 U.S. airports and for most major airlines (including American, Continental, Delta, Northwest, Southwest, and United). They work like ATMs: With a credit card as ID, e-ticket holders can check flight status, select a seat, print a boarding pass, and even check bags at some locations. Often there will be a person standing by to help. Or print a boarding pass from your own computer (for all airlines listed above).

THE EXPERTS

AMY BOHUTINSKY, consumer-travel expert, Hotwire.

DIANA CRONAN, spokesperson, Air Transport Association.

PETER GREENBERG, author.

MARY JO LIPMANN, Travel Watch editor, Orbitz.

ROBERT SINCLAIR, manager of public information, Automobile Club of New York.

DAN STESSEL, spokesperson, Amtrak.

AMY ZIFF, editor-at-large, Travelocity.