At Kingman, which is the junction with I-40.
When the U. S. is on Daylight Saving Time, from the 2nd Sunday of March to the 1st Sunday of November, there is no time difference between Phoenix and Las Vegas. When the U. S. is on Standard Time, Phoenix is 1 hr. ahead of Las Vegas. 4 AM PST = 5 AM PDT = 5 AM MST
Phoenix, Arizona
Phoenix, Arizona is about 287 miles southeast of Las Vegas, Nevada.
It is only a 5 hour drive, but Kingman is a possibility.
It is 285.57 miles according to MapQuest.
ABOUT FIVE HOURS
On US-93.
It is a 5 hour drive.
It is 340.30 miles according to MapQuest.
Phoenix, Arizona
I'd say Las Vegas, NV, as far as major towns.
It is about 30 miles from the Hoover Dam border between Arizona and Nevada to drive to Las Vegas.