When the wife and I went to Monument Valley last year, we had to be very careful to use as little as possible battery.
The trip between Farmington NM and Blanding UT was our first step. We missed one of the turns going there as they are pretty east to miss, and suddently we were on Rt 666, with -3% battery arriving showing!
Luckily we noticed right away and made a u turn on the highway. The only reason it showed -3% was because the next intersection was like 10 miles away. We made it to a very pleasant supercharger in Blanding UT with about 10 miles left and charged to 100% I think it was 298 miles. We made it through monument valley, had dinner in Kayenta and arrived back at Farmington with 8 miles left. That was a bit of range anxiety
I hear there is a Supercharger in Kayenta, which would have made the trip super easy.
If worse came to worse, I'd try to tow to charge trick, or just find a 110V outlet.