I've just watched the last 20 minutes of an episode of Deep Space 9, and towards the end Worf is very insistent that O'Brien and his wife move to Minsk. Is there any in or out of universe reason for this?
If I remember this that is in the last episode, or very near the end of the show. O'Brien had gotten a position teaching at the Academy (on Earth) and Worf, having lived on Earth for part of his life, may have lived in or near Minsk, or at least close enough to the Ural mountains to go camping there occasionally.
The Rozhenko family eventually moved to Earth, where Sergey frequently took Nikolai and Worf camping in the Ural Mountains.
Worf being very insistent is just his way (watch the TNG episode where he tries to get his son to clean his room and eat his dinner).
It was clearly established (in the various EU novels) that Worf's adopted parents, after leaving the Earth colony on Gault, had retired to a small farmholding in Minsk. Worf traveled with them and spent some time there prior to joining Starfleet. Evidently he grew to like the city and its environs.
When Helena Rozhenko opened the door of her modest farmhouse in Minsk, she let out a girlish squeal of delight that did not remotely seem to match her exterior as she saw Worf standing in the doorway. She threw her arms around him before he was able to get a word out, and as courageous as the Klingon was, he had to admit he felt safer in the elderly woman's embrace. "Sergey!" she cried out, summoning her husband. "Worf, why didn't you tell us you were coming ... ?"
Zelik had been hearing stories about the Rozhenkos’ Klingon boy all of his life. The farming community on Gault was a very close-knit one. While the Rozhenkos had retired to Minsk on Earth by the time Leybenzon was a teenager, the stories about them lingered. Not all those stories were pleasant ones. Worf had accidentally caused the death of a fellow teenager during a soccer game.