Denver and New Orleans are about 1,080 miles apart by road. Split the difference and you arrive near Oklahoma City, the city closest to the halfway point between them. That puts roughly 10 hr 34 min of driving on the Denver side and 12 hr 5 min on the New Orleans side — the fairest single meeting point among the cities near the middle.
Over this distance most people will fly rather than drive the whole way. Oklahoma City still makes a fair, central place for Denver and New Orleans to converge, splitting the travel instead of asking one side to cross the country.
If Oklahoma City doesn't have what you're after, Dallas and Austin are also close to the midpoint and worth a look — each keeps the drive reasonably balanced between Denver and New Orleans.
City descriptions adapted from Wikipedia (CC BY-SA); photos via Wikimedia Commons, credited above.