With places, it's all different. Some of the places in my books are real, but a lot of them are made up. I invent the names and layouts of towns and communities (Three Points, in Ghost Medicine, or Los Rogues, from In the Path of Falling Objects) just because I don't want to be constrained to making things a certain way or including things that are unnecessary.
That said, I wouldn't be able to write about places that I've never been, and feel a deep connection to the places in those two books (and I do throw in some "real" places, too).
The Marbury Lens is a bit different, though. The only "made-up" place in that book is the central California town where Jack and Conner grow up. And there are plenty of concrete details about the other "this side" places -- London, Blackpool, Harrogate, Leeds, and Kent -- where Jack spends some time (I've spent quite a bit of time in those places myself).
I'll even drop a serious clue here about the walled city the boys find in Marbury, and even its name -- it's also a real place from the world on "this side," a place I've also been to.
