For better and worse, sometimes it still feels too much like very little in the world of The Expanse actually happens outside of the "campaign PCs" and it makes it feel like a smaller world than it should that much doesn't actually seem to happen until just the moment when the "campaign PCs" show up. The show tries to make up for it some of the time, but that still feels like the core of things. (I have not tried reading the books yet.)

It's a bit of a trope in the books that Holden has a need to get involved in everything. They even lampshade it with Avasarala.