This is a Vietnam era song and conveys the sentiment of any serviceman who did his tour there who was going home to the girl he loved and the land he loved. The verse "I'm so glad that I'm still alive" is a reference to all our fallen comrades in arms who didn't make it. However you do need to correct the lyrics the second time he sings about sleeping underneath the moon. He already talked about the girl he knew there and the second time the Lyric is sung, he says tomorrow night you'll find "us" sleeping underneath the moon at yellow river.