
You'll absolutely love it.
Regarding your 250 mile trip, I finally managed my 2020 Tesla Tour to meet a few forum friends in May 2021 (blasted Covid). I did 587* miles in two days, used 160kWh and averaged 272Wh/mile. So that suggests 275 miles of range. However, mine is a Sep 2020 car, so not as efficient, and almost all motorway driving was done at around 85-90.
Recent testing at 70mph, during that heatwave with the A/C on, was 236Wh/mile but only over 40 miles, and it was still falling as it used quite a lot to cool the car down in the first few miles. So that's around 320 miles.
So ~77mph, I suspect you'll be good for 300+ in the summer, and 250 in bad weather in the winter, but if worst comes to worst, you can always lift off a tad, and Supercharger stations are spreading so, so fast.
*It's a very comfy car too. I hadn't done more than 60 miles in one day for over a decade due to back issues, but as that improves, combined with the great seats in the TM3, I had no issues with the mileage, and was singing along just as enthusiastically to the 'best of the 80's' on Spotify at the end of the trip, as the start.
Only issue I had, was a slight numb / vibration feeling on the side of my right index finger for a couple of days. Turns out, the car is so smooth and stable, that almost all of those 600 miles were done with my left hand resting on my left leg, and my right elbow on the door, and my right index finger resting inside the wheel, but on top of the spoke, so it took all the strain and vibration. May sound like a silly thing to mention, but that's how smooth the car is, even at relatively high speeds**. Our Leaf was almost the opposite, getting quite light and scary in the high 70's, so you had to grip to stay straight, as I assume some of the weight was being lifted off the steering axle by the air flow.
** I say relatively high as I've only given it one real high speed poke, on a straight bit of motorway with no cameras, no bridges, and nobody else about. It was still accelerating rapidly when we hit intercity train speeds, so I lifted off, but still solid, stable, perhaps too calm and cool for average drivers like moi.