Nevada is much more than Vegas. If you happen to visit Vegas, I really advise to book an extra 1 just to explore the state of Nevada. There's so much nature to be seen and cool outdoor pursuits to be done like riding buggies at the sand dunes in Sand Mountain recreation area. You can also go caving at Great Basin national park and see the huge "Crater" at Lunar Crater national Park.
I agree many people going to Vegas probably think Vegas is a state or that Vegas is the capital, which is not. Carson City is Nevada’s capital city and a great place to go with kids. The city has a cool children’s museum with a floor piano children can play with their feet, just like in the movie BIG.
There also plenty of ghost towns to be seen in Nevada such as Metropolis (just outside of Wells) on Interstate 80, and Rhyolite (just outside of Beatty) on US Route 95. Don't expect to see much though, aside from a few buildings still standing.