Final answer:
The 1) spruce-covered island is the detail that best establishes a feeling of solace, providing a serene and natural setting.
Step-by-step explanation:
The detail that best establishes a feeling of solace is the 1) 'spruce-covered island.' An island covered in evergreen spruces suggests a serene and comforting natural setting, contrasting with the starkness of 'hidden under three feet of ice' or the emptiness of 'it was unbroken white.'
Additionally, the mention of a landscape that 'curved and twisted away' could invoke a sense of mystery or unease rather than solace. Imagery associated with trees and greenery commonly evokes feelings of peace and tranquility.