Right. My reasoning for posing this question is that I will likely be the first in my (remote, mountainous) community to own a pure electric vehicle. I am posting a couple of essays in the local paper sort of evangelizing the coming of the long(er) range electric car. Our round trip commute to town is about 150 miles, so the Bolt and the M3 are really the first "affordable" solutions for making that run without having to worry about charging.
Something for mountain residents (or those with weekend cabins, etc.) to keep in mind is that you may need a somewhat larger battery to comfortably make a round trip from high elevation, down to low elevation, and back up to high elevation. That is in comparison to the more typical, easier scenario where a "flatlander" gets a full charge, visits the mountains, and then descends back home.
The reasons for this are as follows:
1. If you start down a mountain with a high state of charge, the battery won't have "room" for regenerative braking. Not only is this bad for efficiency, it means more brake wear, and on a large mountain your brakes could become quite hot since there's no such thing as engine braking in an EV. Further, when you do leave room in the battery, you can't necessarily count on getting a full charge from regen because battery charge rates have to be tapered as the battery gets close to full. So you're generally forced to work with less overall energy for the roundtrip.
2. Your battery will generally be colder if it's spending most of its time at a higher elevation. While Tesla battery packs do benefit from some heating while charging, and can be pre-heated, you're still generally working with a colder battery. Colder batteries hold less energy and do not allow as much regenerative braking. (This is a much bigger issue in a Nissan LEAF due to its lack of thermal management on the pack. When I take my LEAF "down the hill" with a cold battery, I'm forced to rely almost exclusively on the brakes and have to stop on the way down to let them cool.)
Therefore, with a 150 mile round trip from high-->low-->high elevation, I'd recommend paying extra for a larger battery. The base model with the 215 mile battery may not be enough for comfort, especially after several years and a bit of degradation. More like 250+ miles would be ideal, unless of course you have easy access to charging while down the mountain.