Las Vegas and Richmond are about 2,073 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 20 hr 42 min of driving on the Las Vegas side and 23 hr 32 min on the Richmond 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 Las Vegas and Richmond to converge, splitting the travel instead of asking one side to cross the country.
If Oklahoma City doesn't have what you're after, Kansas City and Dallas are also close to the midpoint and worth a look — each keeps the drive reasonably balanced between Las Vegas and Richmond.
City descriptions adapted from Wikipedia (CC BY-SA); photos via Wikimedia Commons, credited above.