The NeoAir pad is not suitable for temperatures below freezing. I have one and it is great three season, but you are better off doubling up on closed cell foam pads at lower temperatures.
I have never spent an unplanned night above timberline. Sometimes you solve problems by hiking to a lower place.
However there are times where you might want to go to the ground to stay above timberline. An example is Segment 7 of the Colorado Trail. We planned to be at the 12,600 high point about 3:00 pm and stayed for the night because the weather was stable. I have a picture of sunrise in my gallery.
I good air/ground kit is a shorty NeoAir combined with a couple of 1/8" closed cell pads.