Yes!
Arrive onto Roosevelt Island by subway on the F train, or for a unique view of the city, take the aerial tramway from Manhattan to Roosevelt Island. You can also arrive by the Astoria Line ferry (catch it from Long Island City or lower Manhattan).
The Sanctuary is tucked away on the northwest waterfront of Roosevelt Island, past the Octagon residential buildings. There is parking directly on site, with additional spots a 90 second walk from the venue.
Cocktail attire, but the ceremony will be outside (weather permitting) so plan for a nice breeze off the East River.