Badlands National Park in southwest South Dakota offers buttes, pinnacles, and spires in one of the largest prairies in the United States. It has the world's richest fossil beds from the Oligocene epoch and wildlife including bison, bighorn sheep, black-footed ferrets, and swift fox.
Great trail to get a taste of Badlands hiking. We saw 3 big horn sheep up close. Beautiful views from various locations (with a little exploring) at the top. Short and easy. The ladder was the most uncomfortable part for me, though some may not like a few narrow turns along the cliff. Have to do a little climbing on gravelly rock, but very manageable.
My kids, age 5 and 9, my wife and I recently hiked off path and thoroughly loved looking for fossils. The rugged and sharps rocks deserve respect, but are perfect for hiking on. Beautiful landscape. Make sure to stop at the big visitors center (Rafiel?). There's lots to see.