I also try to drive in a manner that is friendliest to the battery (ie I'm not accelerating a bunch to pass people or driving 90 mph), and almost all the driving is on a highway. But, that's how I naturally drive in my gas car as well.
I do ~Denver to ~Salt Lake City and back 2x/year through the Wyoming route and I've done it 6 times so far in a Tesla and 4 times in a gas SUV. I do it in the early/late summer so temperatures are warm, which I'm sure helps the mileage.
The tesla mapper site claims you can do it with only 35 mins charging, but I prefer the northern route, and my actual departure/destinations are about ~1hr more driving, but I'm sure that wouldn't add more than 45 minutes to the charging time: https://www.tesla.com/trips#/?v=LR_RWD_NV36&o=Denver,%20CO,%...