Should add that this event happened in Central Mass *during* Vietnam, not *in* Vietnam. :p
I think they might have been heading for Westover AFB, which was maybe 15-20 miles away.
I lived under one of the approaches to Westover as a kid. Those things were noisy!
A few years ago one was flying into a local base for an air show. It was like hearing a song you haven’t heard in twenty years.