I received an email from Lincoln Gunn, who asked me to pass the following statement along to readers of this site. Hopefully it will answer all of the questions I've fielded on Gunn's whereabouts.
"It has been a privilege to represent Princeton University as a student athlete on the Men's Basketball team over the past two years. I am proud of my contributions to the team as a player and teammate. I have made the decision to retire from Princeton Basketball as it is now time for me to pursue the other wonderful opportunities Princeton University offers outside of athletics, including studying abroad, which I experienced this past summer." - Lincoln Gunn, October 2008