Lyric discussion by Groon 

Cover art for Just A Song Before I Go lyrics by Crosby, Stills, Nash & Young

While on the surface the lyrics are simple enough as to need no explanation, on another level, I've always thought that maybe "Travelling twice the speed of sound, it's easy to get burned" might be Graham alluding to cocaine. It was 1977...by then everyone around Crosby saw that his coke use was spiraling out of control. I'd assume that Graham had his own experiences with it too. Then "and when we opened up the door, I had to be alone" part could be wanting to be alone when actually "doing" the drug, maybe to hide it. Also, the "when the shows were over" and "driving me to the airport" lyrics seem to imply a kind of "rock star" or "jet set" lifestyle which goes hand in hand with cocaine (especially in the '70s).

@Groon I think “traveling twice the speed of sound” is referring to the Concorde, launched in 1976. It traveled approximately 1350 miles per hour; the speed of sound is 659 mph at an altitude of 50,000 feet, which is the height the Concorde flew.