I didn’t know the expression had become that uncommon, that people would be unfamiliar with it. Seems like a regular ol’ idiom to me, meaning the same as “sneak away” but more old-fashioned sounding. The question is whether it was more common in 1970s song lyrics than at other times, and maybe it was. I was a teenager in the 70s so I can think of a few examples, but I don’t have other decades to compare to.
…though I do remember saying and hearing ‘far out’. 
That wasn’t the only one, either.
Lois How’d you like your first day on the job?
Clark Frankly the hours were sort of longer than I expected, but on the whole, I mean meeting you and Jimmy and Mr. White - Gosh on the whole I’d say it’s been swell.
Lois Swell? You know, Clark, there are very few people left in the world who feel comfortable saying that word.
Clark What word?
Lois Swell.
Clark Really? It always sounded kind of natural.
Whitesnake, on “Snake Bite” 1978, yep Steal Away it is, fourth track. Every rocker should remember that one.
I’ve heard it occasionally in conversation since the 60’s. That’s as far back as I can personally cover. I seldom heard it.
So you’re angling for an invite to the Pizza Place Marcia? LOL