Question: Why did you base the novel in America, when you are a New Zealander? Why didn't you base it in New Zealand?
Long Answer: I researched the heck out of Castle Rock and its surrounding areas, including Kelso, and Mount St. Helens. In choosing Castle Rock, I took the following things into consideration:
I wanted a small town, near a major mountain sightseeing point. I knew that Mount St. Helens was a very well known mountain, and I was pleased, upon discovering Castle Rock, that it has been labelled "The Gateway To Mount St. Helens".
This was ideal, as one of the themes of my story was that Cassie, our heroine, was at a point in her life where a lot of decisions need to be made, and also she would, in effect, be choosing to follow a path into an almost alternative reality, stepping through a portal, or gateway, into a new and "Extraordinary" life. Portals will also play an important role in later stories in the series.
Mount St. Helens plays an important role in the story, effectively showing off and yet hiding Astra's arrival.
I had, as the story progressed, also developed intricate back-stories for a number of the characters. In that respect, I had them arriving from various places around the world.
My ultimate plan, in this, is to take my readers on journeys to those places, as novels are written telling other character's stories. Alistair and Charlotte, for example, met in France. I plan to base their story there. Yes, I've never been to France. Yes, I intend to research the heck out of it, so that I can create a story that takes my readers there, and in the process, take myself there.
And yes, for my fellow Kiwi readers - I do plan on at least one of my future stories being set here in good old New Zealand.
Perhaps, one day, I'll be able to visit some of these places for real, but for now, GoogleEarth, and the internet, and travel shows, and other books, will have to fill in the gaps until I do.