The fair place to meet is Albuquerque, NM — the city closest to the midpoint of Oklahoma City and Tucson. From the farther side that’s about 10 hr 49 min of driving.
Recommended midpoint
Albuquerque, NM
From Oklahoma City
10 hr 49 min
516 mi to Albuquerque
From Tucson
6 hr 40 min
318 mi to Albuquerque
Tucson has the shorter trip; the split is off by about 4 hr 9 min. The alternatives below can even it out. Oklahoma City and Tucson are about 803 miles apart.
Oklahoma City and Tucson are about 803 miles apart by road. Split the difference and you arrive near Albuquerque, the city closest to the halfway point between them. That puts roughly 10 hr 49 min of driving on the Oklahoma City side and 6 hr 40 min on the Tucson 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. Albuquerque still makes a fair, central place for Oklahoma City and Tucson to converge, splitting the travel instead of asking one side to cross the country.
If Albuquerque doesn't have what you're after, El Paso and Denver are also close to the midpoint and worth a look — each keeps the drive reasonably balanced between Oklahoma City and Tucson.
Albuquerque is the most populous city in the U.S. state of New Mexico. Founded in 1706 as La Villa de Alburquerque by Santa Fe de Nuevo México governor Francisco Cuervo y Valdés, and named in honor of Francisco Fernández de la Cueva, 10th Duke of Alburquerque… Read more →
Oklahoma City, often shortened to OKC, is the capital and most populous city in the U.S. state of Oklahoma. It is the 21st-most populous U.S. city and 8th largest in the Southern United States, with a population of 681,054 at the 2020 census. Read more →
Tucson is the county seat of and the most populated city in Pima County, Arizona, United States. Read more →
City descriptions adapted from Wikipedia (CC BY-SA); photos via Wikimedia Commons, credited above.
Estimates use straight-line distance and typical road speeds; real drive times vary with route and traffic.