Former AF MenTaking River TripGREAT FALLS, Mont. G\P- . Two former Air Force men hitchhiked into Great Falls i Tuesday, parked their kayaks : and took a tourist’s detour to Yellowstone National Park be- ■ tore resuming a transcontinent- l al river trip. 1Jim Curnes. 23, of Wheeling, ] W.Va., and John Davidson, 21, of Carlisle, Pa., planned to head down the Missouri River early next week.They paddled 550 miles up the ' Columbia, Snake and Clearwater J rivers to Kamiah, Idaho. From ' there, they hiked 600 miles to Missoula and caught a ride to Great Falls.After a tough upstream pull cm the Clearwater, they abandoned plans to travel the Clark Fork River from Missoula to Garrison. They had wanted to portage over the Continental Divide and reach the Missouri River near Helena.Curnes and Davidson hope to reach Chesapeake Ray by late October after paddling the Mississippi, Ohio, Monongahela endPotomac Rivers. They started May 19.