Does anyone else do this? (I want to compare notes)
Oh, absolutely.
As someone who works predominantly in historic settings, it's one of the most enjoyable bits in terms of taking a general concept (say, Vampire the Requiem in the High Middle Ages) and actually moving that into a real time and place, both in terms of actually finding historical places and settings into which to slip the idea and make it real, and indeed in bagging some verisimilitude into the setting. Equally, I take the same approach to more modern settings, especially ones which are urban and where the feeling of, say, Philadelphia, needs to be different from Boston or Seattle.
The process can be really satisfying, and getting both the right level of detail and understanding can be really satisfying, especially when you've got a player who perhaps is less familiar with the nitty gritty than you are and you have the opportunity to both slightly subvert their preconceptions and indeed show off something cool which allows them to take a step deeper into that setting. Obviously, that's caveated with the need not to be a total *censored* about it or indeed having a go at a player if they miss a cue or don't quite get it.
My only advice would be with anything is that there's a point where detail, accuracy and realism goes from your friend and becomes your enemy. Trying to use real people then opens bags of worms about trying to represent them correctly, and indeed you end up potentially drowning a player with caveats and the need to create a three dimensional image which is true to fact as opposed to making something which suits your needs. Personally, I tend to read and absorb and then find a gap in history into which I can worm my way, and create a canon for the game which exists between the bricks of recorded fact.
More generally, and perhaps addressing OP's question more on the head, yes, I have absolutely learned about subjects I would never have previously considered through character and setting creation, and I would say it's one of the joys of those processes in terms of adding to a knowledge base.