Think all of Kansas is flat) Think again. The Flint Hills. in the eastern part of the state, fan out over 183 miles from north to south, stretching 30 to 40 miles wide in parts, the land folding into itself, then popping up in gentle bumps, with mounds looming far off on the horizon. Seemingly endless, the landscape offers up isolated images--a wind-whipped cottonwood tree, a rusted cattle pen, a spindly windmill, an abandoned limestone schoolhouse, the metal-gated entrance to a hilltop cemetery. Proud of the region's beauty, Kansas has seen to it that 48 miles of its Highway 177, leading through the heart of the hills, are designed the Flint Hills National Scenic Byway. This stretch starts about 50 miles northeast of Wichita and leads north to the Tallgrass Prairie National Preserve, one of the few place left in the United States where a visitor can see the grasses that once covered so much of the American heartland. While up to a million head of cattle graze each summer in the Flint Hills' rolling pastures, they're long gone from Wichita, a metropolitan area of half a million people, at the confluence of two narrow curving rivers. But when a strong dusty wind blows through, it's a reminder of the city's roots as a wild cow town. The Flint Hills Scenic Byway winds through almost treeless rolling land where bison once roamed they have been replaced by prairie chicken, great blue herons, coyote, deer, collared lizards, bobcats and, of course, cattle. The route starts in the tiny ranch town of Cassoday (population 130), where the dirt Main Street has a few weathered 19th-century wooden buildings housing an antiques store and a cafe popular with cowboys, truck drivers and bikers. It then goes through a handful of small towns and past the tallgrass prairie preserve to Council Grove, a former staging area on the Santa Fe Train. But what this ribbon of a highway offers most is wide-open space. For dramatic effect, visit at sunset when the sky is awash in reds, purples and blues. Of late, tourist amenities have been beefed up in Flint Hills, especially in Chase County, made famous by William Least Heat-Moon's 1991 book 'PrairyEarth.' In Cottonwood Falls, with about 1,000 residents, the two-block shopping district is dominated by the grand Chase County Courthouse, the oldest country courthouse (1873) still in use in Kansas. Made of native honey-hued limestone with a red mansard roof, it resembles a small chateau. In small shops along Broadway Street, a bumpy road paved in red brick, you can find Western gear at Jim Bell & Son, antiques and art at the Gallery of Cottonwood Falls, and bison burger and chicken-friend steak dinners ( $ 6.95) at the Emma Chase Care. One of the town's biggest annual events took place last month, the weeklong Prairie Fire Festival, paying tribute to the annual controlled burning, to clear out old dry grass and promote new growth, an astonishing sight of flames sweeping through the hills. But near Cottonwood Falls, there are guided tours of the high open hills available now on foot, horseback, 1bur-wheel all-terrain vehicle and 19th- century covered wagon. Kansas Flint Hills Adventures offers two-hour tallgrass prairie interpretive tours, wildflower tours and trail rides led by a naturalist who expounds on local history, cowboy culture, American Indian traditions, plants and animals. Wanna-be cowboys can help out with the chores (or not) at the Flying W Ranch, a 10,000-acre, fifth-generation, working cattle ranch to the west of the byway, off Route 50 in the one-building town of Clements. It offers modern bunkhouse lodging, chuck wagon meals, trail rides, longhorn-roping demonstrations and sunset rides in a 1959 Ford wheat truck. In the summer and early fall, weekend pioneers can pick up the Flint Hills Overland Wagon Train in Council Grove. Riders camp overnight and are duly fed several 'pionee