This is not as impressive as you might think, to be honest. What they did is the ideal situation for using EVs: drive short distances and charge overnight.
>> over the course of our 4-night stay, despite driving over 100km per day in the park.
Their needed range was 100km/day, over four days, with overnight charging for each 100km drive.
To get there, they drove for 3 hours, then stopped for 1.5 hours to charge.
Honestly, the story makes it clear that range is an issue, not that range is doable in an EV.