Well I would most certainly recommend the "White Rim Trail" in Canyon Lands National Park, near Moab Utah.
It is amazing, and the sights are something else. Just be sure to check the map for the camp sights. You have to reserve them well in advance, and some of them are only a few miles down the trail. IE a 90 mile trail if you get to your camp after just ten miles that means the second day is going to be a long long day.
"Do you know what a soldier is, young man? He's the chap who makes it possible for civilized folk to despise war." -Allan Massie