One of the most hazardous challenges facing the Oregon Trail pioneers was the wagon crossing of the wide and treacherous Snake River in Idaho, a still-dangerous maneuver that will be re-created this summer in a gala three-day festival. It is just one of many celebrations and other activities commemorating this year's 150th anniversary of the historic trail.

The six states through which the Oregon Trail passes have taken the opportunity of the sesquicentennial to stage a variety of special Old West-flavored events -- including several historically authentic horse- and ox-drawn wagon trains. And local tour operators have put together unusual escorted tours of the 2,170-mile trail by motorcoach, train or even -- for the hardy few -- by overland covered wagon.

If you are among the thousands of Americans expected to travel at least a portion of the trail this year, you can relive the Old West in many ways:

Spend a lively evening at a rousing outdoor musical depicting wagon life on the trail.

Ride a horse alongside a wagon train.

Join a songfest around a wagon train campfire.

Take a ride in the ruts of the Oregon Trail in an authentically accurate prairie schooner.

Listen to cowboy poetry from the lips of working cowboys.

Swing your partner in a prairie square dance.

Activities such as these have been organized in dozens of communities along the trail, and they are scheduled from now through the fall. Several are major events, featuring entertainment by such top names as country-western singer Emmylou Harris. The reenactment of the Snake River wagon train crossing, at Idaho's Three Island Crossing State Park from Aug. 12 to 14, is expected to draw more than 40,000 spectators.

Travelers planning to trace the route of the trail have two options for taking advantage of these programs. They can contact each of the six Oregon Trail states -- Missouri, Kansas, Nebraska, Wyoming, Idaho and Oregon -- for a list of events and schedule their trip to take in those that most interest them. Or they can take pot luck, gambling that they will chance upon one along the way. Which really isn't much of a gamble, because the activities are so numerous.

Among the events:

Overland trek:Wagonmaster Morris Carter departed Independence, Mo., on May 2 bound for Oregon in the same slow, rolling way the pioneers made their long journey 150 years ago. Carter, who heads up a train of five wagons, expects to reach Independence, Ore., (just south of Oregon City) in the Willamette River Valley in early October. You can join him in one of his wagons for a day or a week or more, or ride alongside on horseback.

The heavy-duty Conestoga wagons all have padded seats and accommodate 20 riders. The canvas sides roll up, so riders can catch the breezes and the views. Nights are spent in campgrounds in tents or Native American tepees. A one-day wagon ride with a chuck-wagon lunch is $25 per person. Overnight rides are $125 per person a day. To travel alongside the train on horseback, the charge is $125 per person a day, which includes horse rental. An overnight horse trip is $165 per person.

If you go, plan to dress in 19th-century pioneer attire. To catch up with Carter, a wagon train outfitter, contact his firm, Historic Trails Expeditions, P.O. Box 428, Mills, Wyo. 82644, 307-266-4868.

Most of the Oregon Trail states are sponsoring wagon train treks this summer covering the portion of the trail between their borders. If you want to watch the prairie schooners pass by or snap photos of them, contact the state tourism offices for a current schedule.

The Nebraska Oregon Trail Covered Wagon Train will be on the trail from May 28 to June 28, covering 430 miles at a rate of about four miles an hour. Riders can climb aboard for a day for $20 per person, which includes lunch and dinner. Horses can be rented for $35 a day. Or you can walk alongside the train at no cost -- but a fee will be charged for meals.

Departures are scheduled each morning at 7, and the wagons should complete the approximately 20-mile daily journey by 4 or 5 p.m. To reserve a seat, contact the Nebraska Division of Travel and Tourism, 800-228-4307.

Snake River crossing:As the pioneer wagon trains progressed through southwestern Idaho, they faced a difficult choice. They could attempt to ford the wide Snake River -- chancing the loss of their wagons, their gear or even their lives -- to reach an easier and shorter route to Oregon. Or they could stay on the south shore of the Snake and labor over a longer, much rougher and drier route. Both options had many adherents, but it is the pioneers who chose to ford the river who are memorialized in an annual reenactment. This year's celebration, Aug. 12 to 14, is one of the big events in Idaho this year.

The pioneers forded the river at the site where three islands rise, and they could make good use of two of them. The north shore on which they landed is now called Three Island Crossing State Park, and it is where the reenactment and a variety of other events will take place, among them hot-air balloon flights, cowboy poetry readings, a pioneer crafts show and square dancing under the stars. Emmylou Harris will appear in concert in the nearby community of Glenns Ferry.

But the main event is Saturday morning, Aug. 14, at 11 a.m., when at least two horse-drawn wagons will plunge into the Snake, island hopping to the north shore as the pioneers did. Several other wagons will head out on the alternate trail to demonstrate how the crossing split many trains. And a couple of wagons also will cross on a small, newly constructed ferry of the type that eventually was built to carry the pioneers and which gave the town of Glenns Ferry its name.

Three Island Crossing State Park, P.O. Box 609, Glenns Ferry, Idaho, 208-366-2394.

Oregon Trail Special: Powered by Union Pacific's historic locomotive 3985, the Oregon Trail Special will travel a portion of the Oregon Trail on two six-day journeys between Salt Lake City and Portland. Travelers can sign up for the full six days or ride for only a day or two.

Departing Salt Lake City on May 29, the vintage train joins the Oregon Trail at the Portneuf River near McCammon, Idaho, and then follows the trail alongside first the Snake and then the Columbia rivers, passing through the spectacular Columbia River Gorge just outside Portland. The return trip to Salt Lake City departs June 12.

The trip is organized so that the train will travel only during daylight, with nights be spent in lodgings along the way. The coach fare for the full six days is $650 per person, including a box lunch daily. Accommodations are additional and must be arranged independently from a list that is provided. Transfers between the train and lodgings are included in the fare.

The Pacific Limited Group, P.O. Box 27081, Salt Lake City, Utah 84127, 800-444-3985 or 801-355-5871.

"Oregon Fever":A cast of 45 re-creates the joys and sorrows of life on the Oregon Trail in a two-act outdoor musical drama called "Oregon Fever," featuring three covered wagons, the horses to pull them, a flock of homing pigeons, fiddle tunes and plenty of clogging. Performances are scheduled from July 16 to Aug. 7 (except Sunday and Monday) at Clackamas Community College in Oregon City, Ore. -- the end of the old trail.

A special barbecue dinner is scheduled before the show July 17, and there are Indian-style baked salmon dinners on the weekends of July 23 and 24, July 30 and 31 and Aug. 6 and 7. Show tickets are $8 for adults and $4 for children age 5 to 15. Meals are additional.

Oregon Trail Pageant, P.O. Box 68, Oregon City, Ore. 97045, 503-657-0988.

Overland by bus:A series of 11-day motorcoach tours, tracing the Oregon Trail from Independence, Mo., to Portland, Ore., has been put together by an organization called S.C.R.A.M. Tours or Senior Citizens Roaming Around the Map. They already have filled the departures scheduled for this month, but 10 others are planned.

The itinerary sticks as close as possible to the trail's route, and participants will have several opportunities to see and walk beside historic ruts. On the agenda is a chuck-wagon cookout, a prairie schooner ride, panning for gold and a stop at a Nevada gambling palace. Departures are June 10 and 24; July 8 and 22; Aug. 5 and 19; Sept. 2, 16 and 30; and Oct. 14. The price from Independence is $789 per person (double occupancy) and includes 10 nights lodging and three meals.

Senior Citizens Roaming Around the Map, P.O. Box 1602, Pendleton, Ore. 97801, 800-247-2060.

Campfire songfests: Chimney Rock and Scotts Bluff in Nebraska were two prominent landmarks guiding the pioneers across the Great Plains. They are the backdrop for a variety of wagon train programs put together by a Bayard, Neb., firm called Oregon Trail Wagon Trains. From May into the fall, it offers a nightly wagon ride, chuck-wagon cookout and a lively songfest around the campfire. The ride is only about 15 minutes, but you still get a feel for the jouncing the pioneers experienced on their five-month trek. The trail boss recalls the history of the trail, and then participants watch the cooks prepare dinner in cast-iron pots. The price: $16.95 for adults, $8.50 for children under 12, $1 per year of age for children under 6.

The firm also offers overnight, three-, four- and six-day treks along the Oregon Trail, with prices ranging from $150 to $579 per person, including meals and camping gear.

Oregon Trail Wagon Train, Bayard, Neb. 69334, 308-586-1850.