Sandman, from America's self-titled 1971 debut album, is often said to have been inspired by the 1967 science fiction novel Logan's Run, written by William F. Nolan and George Clayton Johnson. (To cite just one example, you'll find the song included on this list of science fiction references in music.)
Set in the year 2116, the novel depicts a society that has imposed a strictly enforced lifespan of 21 years on its population (expanded to 30 years in the 1976 film adaptation). Upon attaining that age on their Lastday, citizens are required to report to special locations called Sleepshops to be euthanized. Needless to say, some object to this arrangement and attempt to escape their fate by fleeing. The novel's protagonist, Logan 3 (expanded to Logan 5 in the movie), is a Deep Space Operative--also known as a Sandman--whose job is to hunt down and terminate these Runners. In the end, Logan himself becomes a Runner after reaching his own Lastday.
It's easy to see why some have found a link to the novel in the song's lyrics, with lines such as Ain't the years gone by fast/I suppose you have missed them, and particularly the repeated chorus I understand you've been running from the man/That goes by the name of the Sandman. Unfortunately, the link simply doesn't exist. In a booklet included in a retrospective boxed set released in 2000 called Highway: 30 Years of America, band member Dewey Bunnell explains that the song was inspired by conversations he had with airmen returning from Vietnam:
They'd buy us a beer at the commissary and tell us stories about the war. We weren't very political or very military. But "Sandman" came out of our eyes being opened to the fact that these guys weren't much older than us. One of the things that I vividly remember hearing one guy say is that he hardly ever slept in Vietnam--he was afraid to go to sleep. So there's the line, "You've been running from the man who goes by the name of the Sandman"--you don't want to go to sleep because you might be killed. I thought, What a lousy way to live.