Rhyolite is one of the largest ghost towns in America, but gets overlooked as it is on the Nevada side of the state line, barely within the limits of Death Valley National Park. There are few attractions nearby, but I highly recommend you make the journey.
With a onetime population of 10,000, Rhyolite was once the third largest city in Nevada. Las Vegas, in fact, had a population of 800 at the time and was merely a shipping link for goods coming and going to Rhyolite.
As you can imagine, much of the town has crumbled, but you'll be pleasantly surprised by what remains. The main street of town retains many of the building facades, and there is a lovely train station intact, a jail, whorehouse...and the famous "Bottle House" - all included in my travelogue.
Like the rest of Death Valley, there are few restrictions on where you can wander - another huge treat for the kids. Just keep them away from the abandoned mines - mines that yielded no riches as had been promised and hastened the demise of Rhyolite.
What's amazing about Rhyolite is its fast rise and fall. Rhyolite's population peaked in 1907, estimated at over 10,000. It had hotels, stores, schools, hospitals, and even published several of its own newspapers and magazines. Rhyolite was by no means a small town. Then it was struck by financial panic, and people started leaving town. By 1910 there were only 611 residents, then completely abandoned. Today there is a small tourist office at the entrance, and the roads in town are well paved, mainly for tourists. It's a touristy ghost town.