If you're driving along I-40 and have the time, stop in Amarillo, TX and go up to Canyon, TX (about 20 miles). There they have a smaller version of the Grand Canyon. It's a state park (I think it's called Canyon State Park). You can drive down to the bottom and then around the park, can take a trailer and stay for a while (although going down can raise your blood pressure a bit). In the summer they have an awesome outdoor musical theatre show in the bowl formed by the cliffs. The Canyon was the place where the Comanche indians spent their winters as they were protected from the prairie winds and had lots of water from the stream that runs through.