93 North out of Vegas

It is a good road. Yes two lanes the whole way. Easy grade as you head into Ely. Always seems cooler than I expect. People seem to be good about passing and very light traffic. Watch your fuel as there are a couple spots 100 miles between stations.

+1 for the 318 short cut. There are a few small towns to respect the speed limit. We are on this road about every year. Have been around to the east and west and this 93 is the best.

There is a decent GoodSam campground called Valley View just north of Ely if you want to break the journey into two days.

After the first couple of miles north of I-15 it's 2 lane most all the way to Twin Falls.
Not to worry, though. There are numerous passing lanes, and the visibility is so far that the speedies can just zoom right by you. That and that traffic is very light.
All the grades along that route are gentle.
Take Nevada 318 between Ash Springs and Ely to save 40 miles. The final hill into Ely is not difficult.