CHEYENNE, Wyo. (AP) — Organizers are making final course preparations for what they say is this year's toughest U.S. adventure race, an intense scramble across more than 300 miles of roads, trails, mountainsides and open water.

The first-ever Cowboy Tough race begins Thursday at Curt Gowdy State Park west of Cheyenne and finishes Sunday in Casper. Eighty racers in 30 teams are signed up.

The goal of the two- and four-person teams is to reach all mandatory checkpoints and visit as many optional checkpoints as possible. The racers will rely on compasses in many places — global positioning devices are prohibited.

Racers will bike through Laramie and Medicine Bow, canoe across Seminoe Reservoir and pull handcarts at Martin's Cove.

They finish by sloshing down the North Platte River on river-boards and jogging through Casper.