I regard the 'worlds' of Sims 4, for the most part, as regionally linked. San Myshuno, San Sequoia, and Windenberg are all part of SimCity, for instance, but are distinct districts or boroughs within it: Willow Creek is a suburb of it, and Brindleton Bay and Moonwood Mills are more like small towns in the country. Del Sol, Strangetown, Chestnut Ridge, and Oasis Springs are another cluster which I usually play as removed from the 'main' cluster, though how far they are depends on the story: they're not like a continent away or anything, but usually far enough away that going there is significant. Korembi and Sulani are played as distinct Places that people Go To, and when they Go To them, they stay for several days. My sims travel within the main cluster (SimCity) frequently, since I like accepting invitations to go party or prank or whatever. I haven't played with Tomorang enough to know where I want to fit it in, but I'd probably make it another Place that's near Mt Korembi. If Korembi is in mountain country, Tomorang would be at sea level.
When I do homeless challenges, changing neighborhoods always consumes a 'day', so the sim has to wait 24 hours before moving again.