Partial checklist for a cross-country trip, 2003:

A digital camera, extra flash cards, iTunes player, batteries, credit cards, GPS receiver, cell phone, satellite radio, video games, sunscreen, Dramamine, cosmetics, five pairs of sandals, two cases of soda, a pallet of Cheeze Wonkers, a Segway for the campground and the most recent Simpsons DVD for the on-board theater in your climate-adjusted, sleeps-10-or-more RV.

Partial checklist for a cross-country trip, 1804-05:

Muskets, muzzle-loading flintlock rifles, small cannon, sextant, brass kettles, blacksmith's forge, espontoon (spear-like staff), oiled linen (for use as sails or tents), gunpowder, mosquito netting, liniment, medicines, one pair of low leather shoes, two pairs of socks, six kegs of brandy and 2,800 fishhooks — all in two pirogues (canoes) and one 55-foot keelboat, with 22 benches for oarsmen.

Lewis and Clark Voyage of Discovery Preparation: March 1803-May 1804 Start: Camp Wood/Camp River Dubois, Ill. (north of St. Louis) Start date: May 14, 1804 Finish: Fort Clatsop, Ore. (south of Astoria) End date: Dec. 7, 1805 One-way, westbound distance: Approximately 3,500+ miles. Modern-day states crossed: 11 Return journey: March 23-Sept. 23, 1806 Key rivers traveled: Missouri, Snake and Columbia

Makes you appreciate your good ol' cupholder a little more, doesn't it?

Such a travel truth becomes clearer now that the timeline of the Lewis and Clark expedition's bicentennial has begun streaming across our calendars.

August 1803: Keelboat construction completed, Pittsburgh.

Original due date: July 20; finished late due to a boatbuilder more inclined to tip the bottle than finish the hull.

The goal of the journey? Explore North American's little-known interior and fulfill President Thomas Jefferson's commission to search out "the most direct & practicable water communication across this continent for the purposes of commerce."

It was daring, unpredictable, audacious.

In response, lots of history-minded, adventure-admiring Americans today are plotting vacations (now through 2006) that retrace some portion of the storied route traveled by Meriwether Lewis, William Clark and the Corps of Discovery (involving perhaps as many as 45 men) between 1804 and 1806.

If that includes you, consider adding another item to your travel checklist: a good guidebook, one that casts a modern-day light on land routes that closely track the 200-year-old route followed by the Corps.

A nice assortment of such titles exists:

"National Geographic Guide to the Lewis & Clark Trail," by Thomas Schmidt ($16, National Geographic)

Schmidt's guide, a 2002 update of a book first published in 1998, is suited to readers who most care about the history and stories of places touched by Lewis and Clark.

Each of Schmidt's entries involves important dates and places involving the Corps, then explains events of interest that occurred at these stops. Schmidt then offers a short, helpful recommendation for best experiencing the area today.

North of Vancouver, Wash., for example, Schmidt suggests visiting the Ridgefield National Wildlife Refuge and strolling the Oaks to Wetlands nature trail. The Corps, he notes, camped here only briefly in early November 1805, likely due to the racket caused by so many geese, ducks and cranes. Quoting Clark: "I could not Sleep for the noise. They were emensely numerous and their noise horrid."

Expect no lodging or dining suggestions outside of occasional thoughts on camping possibilities. The compact book offers color photos and maps, plus interesting sidebars and outtakes from journal entries. Lewis, we learn, nursed a seriously ailing Sacagawea back to health in 1805 near Great Falls, Mont., with sulphur water and "poultices of Peruvian bark and opium." (More info: www.lewisandclark200.org)

"Traveling the Lewis and Clark Trail, Bicentennial Edition," by Julie Fanselow ($15.95, Falcon Guides)

Fanselow, who has been researching the journey of Lewis and Clark in earnest since 1993, presents a worthwhile balance of historical reflection and contemporary pragmatism in her detailed, 300-page book.

Each of her chapters, which proceed east to west (and even reach back to pre-Voyage events of 1803 in states east of St. Louis), effectively intermingle past and present, making sure you know where to turn and what to watch for as you travel back roads and small towns in pursuit of Lewis and Clark's footsteps. While providing practical details, Fanselow's text manages to maintain a literary, storytelling quality.

All chapters end with long lists of lodging, camping and dining choices. Options she considers noteworthy occasionally get mentioned in her main text, such as the Retreat at Someday Ranch on the Weippe Prairie in western Montana, where a tepee (with cots and sleeping bags) for up to five people can be secured for $35.

Fanselow also points out seemingly every possible visitor center, museum, park, Native American historic site and outfitter (should you want to hop in a canoe or on a mountain bike yourself for a nonmotorized taste of the trail) along the way.

Most references include hours of operation and phone numbers. She also provides a suggested itinerary for motoring the entire length of the trail in two weeks. (More info: www.falcon.com).

"Along the Trail with Lewis and Clark," by Barbara Fifer and Vicky Soderberg ($19.95, Farcountry Press, the publishing arm of Montana Magazine)

Presented in a large, workbook-like format (8.5" x 11"), Fifer and Soderberg's book serves up an appealing car-seat companion for those road-tripping the path of Lewis and Clark.

The authors' main text is devoted almost exclusively to historical accounts of the voyage (divided into chapters according to significant dates), and those stories are then juxtaposed next to modern, color maps that show where the Corps' path traveled and how you can stick close to it.

Thus it serves as a quick-reference tool as well as a fairly detailed historical review.

The map call outs points of interest that yield some "How about that?" reveries as you motor along designated routes.

Then, at the end of each chapter, you get a laundry list of places to visit, things to do (even trail descriptions), plus lodging, campsites and dining options found on each map section.

For a condensed version of the book (with an emphasis on the maps and less on history), consider "Along the Trail with Lewis and Clark Travel Planner and Guide" ($3.95).

Admittedly, it's loaded with ads for Days Inn and the ilk, but it contains enough helpful, insightful information to satisfy the casual yet curious traveler.

Fifer has also authored a variety of other books related to Lewis and Clark.

Her kids-oriented "Going Along with Lewis & Clark" ($11.95) is a well-conceived larger-format book appropriate for grade schoolers and up. Her "Lewis & Clark Expedition Illustrated Glossary" ($11.95) also makes an informative, fun, quick read for kids and parents. (More info: www.lewisandclark.com; 800-821-3874.)

"Bicycling the Lewis & Clark Trail," by Michael McCoy ($16.95, Falcon)

Published under the banner of the Adventure Cycling Association, McCoy's book presents an inviting, thorough guide to a 3,254-mile route from Hartford, Ill., to Astoria, Ore.

You'll get a touch of history in each chapter, but the book correctly spends most of its time telling you where to travel, where to camp and what side trips are worthwhile.

The route varies from 151 miles of continuous bike trail (Missouri's Katy Trail) to the rigors of a gravel incline up and over Lemhi Pass (on the Continental Divide near the Idaho-Montana border). He also reminds cyclists that Montana's famed but rough-rolling Lolo Motorway will involve restricted visitor quotas in the next three years.

An eight-part map series, sold separately, can be used in association with this book. Even without the maps, McCoy's book outlines a fascinating travel opportunity for any two-wheeled traveler in search of a challenge. The book includes black-and-white maps, 12 color panels, mileage logs and a suggested itinerary that could carry you over the trail in 40 days, riding 45 to 113 miles per day. A fine idea-starter. (More info: www.falcon.com)

Terry Wood is a free-lance writer who lives in Bellevue.