I have an Intrigue coming out in '09 (and possibly two more as part of a series about three brothers) that is set in southern Colorado. The mountains, the ringed-in valleys, the wildflowers, the waterfalls. Right? I'm not quite sure because I've never been there.
Don't get me wrong, I did my research on the Internet. I looked up flora and fauna and temperatures and distances between certain cities. I researched the Indian tribes in southern Colorado, and looked up dude ranches and other activities. I'm pretty certain I didn't make any blunders (like having perfectly sane people lying out on the beach in their bathing suits in Carmel, CA - not done, too cold). But I'm wondering if I missed the essence of southern Colorado. You know, those little things that natives take for granted and visitors can discover on their own.
On the plus side, when you don't actually know a location intimately, you don't get bogged down in the details that only locals would find interesting. I set one of my first books (as yet unpublished) in L.A., a city I've been living in for many years and know very well. I couldn't wait to load the book with all the streets and places and quirks of L.A. Later I realized those details slowed down the pace of the book (another Intrigue where the pace must be fast).
I plan to visit southern Colorado in the near future. Hopefully, before I finish the two books in the CO series. In the meantime, I must rely on my Internet research, beautiful pictures like the ones here, and kind friends.