Drive don't fly. Rent van or large jeep. Sleep in it.
I’ve done tours like that through Europe with the S, the 3 and the X. Can sleep comfortably in all of them as one person. In the X, it even worked with my wife and kid (plus baggage for a one week tour).
Can’t speak about the charging situation though down there. If you have to wait in line at chargers while depending on running the A/C all day it might be less fun.
Park literally anywhere not obvious, it is only one night. I am not sure how charged up you need to be to maintain a comfortable temperature. 5%? Just go and problem solve on the road. You'll be fine.