The yard was a white wilderness, full of half-heard sounds that echoed strangely amidst the storm. The icy trenches rose around them, knee high, then waist high, then higher than their heads. They were in the heart of Winterfell with the castle all around them, but no sign of it could be seen. They might have easily been lost amidst the Land of Always Winter, a thousand leagues beyond the Wall.

Excerpt from
A Dance with Dragons
George R.R. Martin

Context: they were in Winterfell, a castle which is being hit by a severe storm. And the Land of Always Winter is north of the Wall while “they” are in Winterfell, south of the Wall.

Hi. Does the underlined part mean it seems as if they were lost amidst the Land of Always Winter, with “might have” meaning “as if”?
Thank you.

I find his turn of phrase here an awkward failed attempt to simulate antique English, a la Tolkein, maybe. But yes, I believe he meant what you say.