update. My night of madness, worrying and worrying about this charging trip was of course ridiculousness. I learned.. "trust the car".. I had plenty of range to get to Ukiah. It's hard though to really believe just how much range you gain from going downhill vs up hill. I was actually ended up with more range than I started with for quite a while (I was staying at the top of a steepish hill). I also learned that of course slow driving is incredibly efficient. The very twisty mountain road limited my speed anyway but keeping it around 30mph I was using very little power, gaining everything I lost going up hill on the downhills.
Bonus was the incredible drive. This drive from Gualala to Ukiah was stunning. Incredible driving road, stunning forests, beautiful rivers. There were also several wineries and breweries on the way that also offered free Tesla charging as well as delicious cheese, wine and beer.
It was a bit ridiculous to drive 140 mile round trip just to charge and I probably ended up with only 70 miles more than when I started but that was after some more "spirited driving" on the return journey up the mountain and gave me plenty of range to take the family home the next day. So trust the car, trust the car, trust Tesla
