Plan on 5-6 houra. It s an hour to Claremont/Pomona, another hour and a half to Barstow then 2 1/2 hours to Vegas. You will stop at least once to eat and use the restroom. Take it easy, Las Vegas is open 24/7, 365 days a year except leap year when it s 366 days. Of course, weekends the traffic is heavier and the accidents will slow you down some.
4 hours, depending on your route, traffic, and your driving. Keep in mind, if you enter Vegas from the south end of the strip, you could actually sit in traffic for 1-2 hours, which of course would then be added to the time of your trip.
I go back and forth often , it is usually exactly 4 hours even if you stop quick to grab a bite. Unless there is traffic then 5 or more.
4 hours if your going without stopping, if you plan to stop by Baker to eat and look around then i would say 5 hours.
Between 4 and 5 hours depending on traffic and your speed.
On a low traffic day just over 4 hours
4-5 hours. maybe more on holidays