Ellri said
If we've got basically standard earth atmosphere, those mountaintop residences should not exceed 5090 m (16700 feet) in height above sea level. Thats the Earth limit for where higher up there is no possibility for growing/raising food. Even then, its hard. Just curious about that kingdom... What made them establish a trade emporium? Wouldn't such make more sense in a society near rivers or major roads?
And for the most part, they don't raise their own food. Outer mountain-towns have farms, but the cities don't bother. It's 'below' them, both figuratively, metaphorically, and literally.