The Universe Within 12.5 Light Years

For getting the feel of the milky way, I think there's nothing that is better able to simulate it than a video game, ala Elite Dangerous. I loved to navigate its galaxy map. The size of the Milky Way, the numbers of stars and distances between them are of scale in there if I recall correctly.

One particular "feel" that people often get wrong: on a scale of up to around 1000 light years in each dimension (on the order of a million stars, or a hundred thousand sun-like stars - I haven't done the integrals over the density), the placement of star systems is largely homogenous. Most galaxy-scale structure (such as the spiral arms, or core vs rim) only starts becoming significant when you get bigger than that.

Now there are 2 caveats to this - first, there is a measurable density difference as you get closer to the galactic plane. And second, globular clusters do do their own thing.

What this means for fiction is that you must commit to either:

* The overwhelming majority of systems must be irrelevant; relevant systems are hundreds of lightyears apart (it is trivial to disappear into uncharted systems assuming you can maintain your spacecraft), and galactic structure does matter. Or,

* If even a modest percentage of systems are to be relevant, then you can't care about galaxy-scale structure at all. And you need to have something stopping people from gratuitously flying out of bounds (this might be as simple as "no compatible languages and no compatible fuel pumps").