To get from Vegas to Cedar City you simply drive north on I-15 for about 2 hours. Or, you can drive through Valley of Fire and then take the scenic drive through Zion Nat'l Park, and then detour on the dirt road that moves through Kolob Canyons, eventually dropping out of the sky and 'down' (elevation: 5800 ft) into Cedar City about 8 hours later.
After about 4 hours of 20 mph zigzagging, and right about the time that I was wondering if I'd made a major error and would have to turn around, a big truck towing a dirt smoother (think baseball diamond) approached. Surprised to see a convertible slumming it on his dirt track, he slowed to chat. I asked him if this road would get me to Cedar City. "Heyull yeah!" he shouted proudly. Put at ease, and happily inhaling the swirling dirt from his passing, I eagerly continued on and eventually found civilization again.