So...you say you want to buy an electric car?

The Tesla superchargers are for Tesla's only and are along the Interstates about 140 miles apart . They are put in by Tesla and if you have a Model S or X you get free charging from them . If you buy a Model 3 you don't, but you can buy time.

Unfortunately at this time there are several different types of connections making it a bit of trick for other vehicles to charge.

But worse come to worse you can charge at any 120volt 15amp outlet, but that's not practical for a long trip. If you have a 240v 30a or 40a charger with a 50a cord you can use an RV Park or Motel to charge but it will take quite a few hours to charge.

There are several private companies that have chargers located restaurants , motels, business, shopping centers around the country.