Early in the Commodore’s career with Thomas Gibbons, he was captain of a steamboat named The Bellona. While the Commodore ran the boat, his wife was up to business ventures of her own. The couple purchased a New Brunswick hotel that was in ill repair and renovated it. Sophia named it Bellona Hall after the steamship her husband was running.
While browsing some of Ancestry’s historical newspapers, I decided to do some searching on the Vanderbilts and found an article from the February 10th, 1901 issue of The Fort Wayne Journal Gazette of Fort Wayne, Indiana that had a sketch of the hotel. 
The article is not entirely legible, but it does begin by recounting some of the history of how the Commodore made his fortune. In the article, it states that the hotel was built in 1803 and at the time of the article it was being used as a tenement house. Apparently, Sophia did a great job running the hotel while it was under her command for 12 years though, as an article from the New York Times from August 4, 1901  indicates that the hotel attracted so much business for the line the Commodore worked for that his salary was increased to $2,000 a year. I thought the sketch was interesting; up until now I’ve not see any images of what the building looked like. In May of 1908, the hotel was sold at auction for $15 (back taxes owed on the property) to a lawyer named Thomas H. Hagerty. 
Just as an FYI, that same Fort Wayne article also had a sketch of Alfred Gwynne Vanderbilt, a great-grandson of the Commodore, which I have added to his genealogy page.
 The Humble Beginnings of the Great Vanderbilt Fortune. Fort Wayne Journal Gazette, 10 Feb 1901. [Link to Ancestry.com]
 Mrs. Vanderbit Kept a Hotel. New York Times, 4 Aug 1901. [Link to article]
 Old Vanderbilt Hotel Sold. New York Times, 16 May 1908. [Link to article]