I’ll let you see yourself how Andy got to Roosevelt Island by inviting you to view Episode 4 below. Unfortunately the method used was a one way experience and Andy had to walk back to Manhattan as he did not have a Metrocard or money for one. I am also not sure why neither he nor his traveling companion thought of taking the Tram back. I will say that if I had the power to travel to Roosevelt Island in this manner at night I’d take it. Beats taking the subway that's for sure.
After you view the episode take a look at the header for each of the Fourth Floor web pages and you'll note a subtitle that relates to the transportation method used in this episode. Kind of makes you wonder if someone in this group lives here on Roosevelt Island.

