This aircraft, and many more, can be seen at the U.S. Army Aviation Museum in Alabama. Though known for her Navy service the Neptune was also flown in during the Vietnam War by the U.S. Army as the AP-2 in service with the 1st Radio Research Company (Aviation) under the call sign "Crazy Cat" for SIGINT (signal intelligence) purposes.
Pasting the museum's name into the search window will bring up posts about the museum as well as other aircraft there.