During the winter you can work your way over to Hwy 95. This will take you all the way to Vegas. The road isn't too bad but it does have a rumble strip in the shoulder so you will be riding close to the white line. There are a few places where you won't have any stops for water or supplies for more than 60 miles. It can be a little desolate and in some areas there is very light traffic. It is definitely desert nearly the entire route.
During most of the rest of the year you could take Hwy 395 to just south of Lone Pine. Then you can take Hwy 136 and 190 through Death Valley and continue on to Beatty, NV. Then take Hwy 95 south into Vegas. There are many more places for food and water and the scenery is much better. There is more climbing than the Hwy 95 route. There are a couple of passes over 8000 feet so they can get quite a bit of snow in the winter. I wouldn't advise going through Death Valley during the summer (unless you like 115 degree days) or Hwy 95 during the summer. It does get really hot and it is very dry.