Which way to go...

My son and I are planning on heading south through Las Vegas and on to Flagstaff to start our trip. We'll stay on I-40 until Amarillo, then the decision comes in. Do we head south into Dallas/Ft. Worth and see the South or do we keep to I-40 and go through OKC. Decisions decisions. A big part of me wants to go through the south. That would probably be the best. But who knows. we still have lots of time to think about it.