In nine years of racing, only 28 men and 2 women have completed the full route to Nome, including Tim Hewitt, a lawyer from Latrobe, Pa., who reached the finish on foot in 2001, 2004 and 2008. About 90 percent of the entrants have dropped out along the trail.

Only seven racers have registered for the 2009 contest, including Hewitt and Basinger. Partly to generate future entries, the organizers have continued to operate a simultaneous 350-mile race ending in the village of McGrath, about a third of the way to the finish. For this shorter course, 43 men and women have entered under the flags of Britain, Japan, Spain, Australia, Italy, Germany, the United States and (separately) Alaska.

For the early December training session, four racers arrived. There was Aidan Harding, 30, a mountain biker from Princes Risborough, England. Despite his lack of experience on snow, Harding was considered a serious racing prospect. There was George Azarias, a young Morgan Stanley banker from New York. A practiced hiker, Azarias had little cycling experience.

And there were Jon and Denise Whyte, a married couple in their early 50s with five children from previous marriages. The Whytes, veteran distance racers, intended to ride a tandem bicycle of their own design. Though Merchant had sought to dispel them of that notion, he could not bring himself to refuse entry outright, largely on account of Jon Whyte’s reputation.

Whyte, a successful veteran of Formula One auto racing crews, had left that sport to design a renowned line of full-suspension mountain bikes bearing his name. For the Iditarod trail, he had built a two-seated silver contraption with a single-wheeled trailer meant to bear the survival gear of a second rider without the additional drag of carving a second rut in the snow.

As the late-November snowfall blanketed the strip malls of Wasilla, Merchant drove his charges in an unheated van to a remote parking lot. The racers piled rucksacks and bicycles into an eight-foot plastic bin hitched to the rear of a snowmobile. As the machine kicked up powder and exhaust, the racers made their way to a hilltop, where piles of snow had buried picnic tables.