According to Agent Finch, there are only three Systems Operations Corporations, but only one of them has both John Rainbird and Gill James working there, and that specific building complex is located in Colorado.
The poem Rainbird recites at sunset is Poem 30 (Others, I am not the first) from "A Shropshire Lad" by A.E. Housman.
In the town of Rivermead, there is a movie marquee listing the movie "Santa Ana", starring Eve Watterson; Eve Watterson was a production manager on this miniseries.
At the end of the miniseries, Charlie gets on a Greyhound Intercontinental bus to Edmonton, Alberta, Canada.