Tesla's Semi truck has already made some city-to-city trips, but how does it fare on cross-country jaunts -- you know, what it'll be doing when it enters service? Just fine, if you ask Elon Musk. In response to an Electrek piece on the Semi's latest visit (to Arkansas trucking behemoth J.B. Hunt), the CEO noted that the Semi has been traveling thousands of miles entirely by itself, using the existing Supercharger network. The only necessary help is an "extension cord" to help the truck plug in. To be exact, it's a system of cords that plugs into multiple stations at once to top up the Semi's giant battery before the company's Megachargers come online.