Quote Originally Posted by Rynjin View Post
Not too many stories of the type very interested in space travel at all. Kind of...adjacent genres? One kind of takes the role of another. If there's space travel you can just make Planets of Hats. If there's multiple universes you don't really need space travel.
Pretty much. In general, whether utilizing space travel or multiverses the device has the same purpose, get beyond the boundaries of Earth, and both can be as limited or expansive as necessary. Settings using FTL can make it highly restrictive, allowing access to only a handful of star systems (naturally occurring rare wormholes is often used for this method), or massively expansive allowing stories to operate on galactic scale (theoretically one can go beyond that, but it's largely irrelevant to do so). Restricted multiverses are also possible, with only some small number of planes of existence in total (many mythological realms are like this).

There are some highly expansive universes that include massive space travel and also multiple dimensions/timelines or other factors that qualify them as a multiverse, though this is rarely their focus. For example, the Culture Universe includes references to a multiverse, such as the titular Excession, but is primarily concerned with galactic society. A limited universe with both would be very rare, I believe.