I visited the estate last year for the first time, and I loved it there. Interestingly, I asked several tour guides about the estate's Titanic connection, and none of them had a clue about it. I was hoping to learn something new about Mr. Wheeler and the Vanderbilt/Titanic story, but I ended up being the one telling the guides what I knew of it.
Offhand, I recall hearing that in the estate's archives there is a letter from (I believe) Mr. Vanderbilt's mother-in-law expressing her relief that they had chosen to sail on Olympic. Also, in a pretty popular picture of Titanic's second class promenade area, one of the gentlemen seen walking there has been identified as Mr. Wheeler.