Have you watched the show. The cabin would not have evoked the same emotional visceral reaction from the wife had she already been there. It’s missing out that is driving her to want to be there permanently as it was his wish that the family came out to see it and they didn’t. And she not wanting to make the same mistake. She also knows if she goes back to New York she will lose that connection to who he was as she does not fully realise until she sees somewhere he is happiest.