Where do you get 265 miles from? I don't know which model year and which version of Bolt you're referring to but per
Compare Side-by-Side, EPA range rating on '22 Bolt EV is 259 miles and EUV is 247 miles.
I sure wouldn't want to attempt 263 miles on a mostly highway drive w/o charging at all, esp. w/o checking elevation gain/loss (below).
Keep your speed down if you need to have more range autonomy. Have you checked the net elevation gain/loss via
Earth Versions – Google Earth? You could be in for surprise in one of the directions.
Chevy Bolt EV travels 750 km (466 miles) on a single charge was when only 60 kWh Bolts existed. Notice they took 25.5 hours? That meant their average speed was only about 18 mph.