• You must start with 78 square miles (200 square kilometers) of uninhabited land not contained in any township. (Not too hard in Nevada, but you might need to buy out a rancher to get something nice. There are single ranches this size. The size is suspiciously close to one which is currently on the market with good interstate highway access.)
• Initially you appoint a 3 member board to run things.
• You can a la carte take over various government services administered by your county, the sorts of things which are usually delegated to towns. (In the US all land is in a county, but only populated areas are in towns, the rest is "unincorporated" and is administered by the county.)
• Once the population hits 100 people, you have to have an election and the elected board replaces the appointed one.