• cars hold more than 1 person
• mountains mean that four hours is now three hours
• cold weather means that four hours is now two hours
• mountains plus cold weather means four hours is now one and a half hours
• much of the (us) country lacks charging stations to support that, or even the infrastructure to support the charging stations
• hybrid cars are the worst of both worlds
• 300 miles is just barely under the safe distance between most major towns \cities in parts of the us
• that means you barely or don't get to your location on one charge
• current charging infrastructure means taking a couple hours extra on many trips right now. At least some of this is improving, but very slowly.

This is a very real problem. We know, we have family with an ev who need to travel to us to visit on occasion.

In general Li ion batteries lose about 40% charge efficiency in normal cold weather. It's up to the car's systems to keep the batteries heated to reduce that, at the cost of constant power draw. In our experience with similar weather it's not far off, and for safety reasons we just assume half the battery is lost during winter driving. Mountains add into that, but aren't ultimately super extreme.