The third panoramic version has the most sky cropped; about 2/5 of the sky in the second version is gone, which I think is about the optimum amount. Since the peaks fade off into the mist, I like the idea of not knowing exactly how tall they are; leaving some sky makes one wonder just exactly how tall they are, but too much sky draws attention away from the mountains. I'm not against the notion of making a narrower crop from the panoramic version, but it needs to be just a bit wider than 3:2 aspect ratio to work for me. A 2:1 crop made by chopping off the left side of the 3:1 panorama seems promising, for the following reasons:
1. The notch in the mountains on the right is a center of interest, as is the one on the left. But the one on the left is less so; there's just not as much going on over there. It's competing for attention, but doesn't have as much to offer. So lose it.
2. The SUV on the road IMO is important to establish a sense of scale to convey how big the mountains really are. Normally one would compose an action shot so that the action is going into the frame rather than out of it; you show where action is going rather than where it's been. But this image is all about mystery and ambiguity and
not revealing the full extent of what's going on, so
not filling in the details of where it is going kind of adds to that whole mood.
3. The 2:1 crop kind of has a sense of the road appearing out of the sagebrush and then disappearing back into it which is somewhat diminished in the 3:1 crop. This is another factor that contributes to the overall mood of the image.
After all that build-up, you can see the 2:1 crop
here. It's a 370KB JPEG. Hopefully someone will find this rambling useful.