Palo Duro Canyon is a must see. Often referred to as "The Grand Canyon of Texas" it is the second longest canyon in the United States, after the Grand Canyon in Arizona. It is about a 45 minute drive south of Route 66 (I 40) but it is a side trip worth taking. If you plan on camping there, they have ample campgrounds both primitive and electric. The Canyon has been used as a campground for over 12,000 years. Must have something going for it. To get there, take I 27 South from Amarillo toward Canyon, Texas. Watch for Texas State highway 217 after the Canyon exits. Signs are plentiful.