Yeah, that's the basic premise of the Ring of Fire books.
What I like most about the series is twofold:
One, they're relatively accurate from a historical perspective; for example, while not all of the "down-time" people are actual people, a lot of them are based on real people and families; for instance, Rebecca Abrabanel herself didn't exist, but the Abrabanel family did, and they were a well-known line of Jewish financiers.
Two, they pay attention not just to the big names in the conflict (e.g. Gustav II Adolf, Axel Oxenstierna, Johann Tsercles, and General Wallenstein), but to how the actions of the big names affect the little guys.