Right off the bat, the poem gives us this: "This house has been far out at sea all night,/ The woods crashing through darkness, the booming hills" (1-2). So, was the house literally out at sea? This is your first big test in interpreting the poem. If you determine that the house really, in fact, was out at sea, it's going to make everything else… well, kind of confusing. Another option, though, is to see this business as an example of that old English class stand-by, the metaphor. Let us explain:
How is a house surrounded by wind like a house surrounded by the ocean? Well, wind is wavy and fluid—a strange substance without any solidity. So, being isolated out on a windy, rural landscape is kind of like being out at sea. Now, in the world of metaphor, this translates into simply being out at sea—no "like" or "as" about it.
This image buffs up the isolation theme of the poem. Human beings, like the people in the house, are in a fragile state, and subjected to strange and unpredictable forces. We're all sailors journeying through a strange, unpredictable, and somewhat frightening cosmos, headed we-don't-know-where.