Interesting tidbit I found this morning.
Was re-reading the graphic novel "Debt of Honor" by Chris Claremont and noticed the mention of "Watchtower" class outposts being built out toward the Romulan neuteral zone. Mind you this was published back in 1992 well before we got the Watchtower class Vanguard station in the novels. Of course, in the graphic novel a watchtower class station is shown to be built on an asteroid. Still found this interesting.