You know, I don't know about this exact situation, but I just did a ski vacation with my model Y. The distances weren't super long but the mountain climb was significant. Basically we rented a place at 1400ft and every day drove to the lodge at 6000+ ft. We had snow tires on admittedly dumb 20" wheels, car loaded with 5 people and all the gear. We did this routine for 4 days in a row. I think the actual distance was only like 20 miles or so but I don't remember exactly.

Leaving the rental at 80% battery every morning and then returning at the end of the day at about 61%. The temperature ranged from 23F at the coldest to 36F on the warmest day.

Obviously a bit of a worst situation for EV efficiency.

All in all the efficiency didn't really matter much, there were 6 ev chargers at the top of the mountain, though usually full ( one time a jeep double parked blocking two of them, fuck that guy). Though I didn't used them this trip as I would just charge at the rental overnight.

Our trip to the rental is probably also a terrible situation, we left with 80% and arrived with ~40% on a somewhat short 60 miles. It took over two hours though due to heavy traffic.

We've done a bunch of road trips in this car over the last two years and what I've learned is that none of this stuff really matters for our lifestyle and location. Yeah winter wrecks efficiency. Yeah large wheels and snow tires wreck efficiency, stop and go with 5 people and all their gear in the freezing cold wrecks efficiency ,but even doing day trips to the mountains is fine, that's when I plug into the charger while I ski. I had to get gas in my previous car for the same trip (Hyundai suv) which is annoyingly at the bottom of the mountain.