If you keep your speed below about 65 mph, you can probably do this round trip with one charge, IF the Supercharger is at or close to your destination. (Doing the trip this way would almost certainly take longer than if you charged it twice...even if that seems counterintuitive) Otherwise (meaning almost definitely) you'll be charging at least twice on this trip, so plan your time accordingly. As others have suggested, use www.abetterrouteplanner to see what the trip will look like, and be sure to adjust the "Detailed settings" to reflect the reality of the temperature and weather conditions and the speed you plan to drive Signed: experienced EV road-tripper.
Tesla has only a little latitude. They can use the 0.7 scalar, and perhaps they could sandbag their rolling resistance numbers to hurt the range of the test. That appears to be what some other EV manufacturers do (notably Porsche - not sure how else they get such good alignment of real world to EPA results, though have not studied it closely). They can also do voluntary range reduction, but I do not know exactly what circumstances allow that, plus it’s also kind of silly, because it just further obfuscates the issue. All of these options are poor. Each one makes true efficiency a more and more abstract concept. I guess because it seems like it wouldn’t be that difficult to make a uniform dyno test which gives the realized efficiency in a given highway test without any scalars, and also provides a usable capacity number, and then there really wouldn’t be much confusion. Since highway range is what people are nearly always complaining about. The scalar issue alone makes this quite a different ballgame than the standard fuel economy tests, because it allows EV manufacturers to scale their results by quite a lot (only a couple choose to do so). I don’t believe this degree of freedom exists for gasoline FE tests though I haven’t studied them closely. There’s an argument for the scalar of course - it rewards better efficiency in cold and hot weather (and a fifth test US06 - which would reward aero slightly). That’s important to some people and manufacturers should have such an incentive. But it artificially boosts range in ideal conditions. Yes. And once you’ve done a route a couple times using ABRP (or carefully estimating yourself) you’ll just be able to use the in-car Nav, and you’ll know how to ignore its suggested stopping points, which are sometimes silly especially on Supercharger-dense routes.