You know, I've also just started working on a Dark Tower game. I'm just wondering, are you planning on following the plot of the series, or are you going to make a different plot based on the world(s) King established? See, I had an idea for a related, but different, plot. Maybe we could combine our ideas or something?
I'll send you a PM explaining it. I'm assuming you've read the whole series, but just in case I'm wrong, I'll put spoilers in a... well, a spoiler.
Also, I'd really recommend using XP as opposed to 2k3. 2k3 is fine and all, and the default battle system is much better than the default XP one, but just using the scripts from this site, even just ones made by Blizzard, will easily make the whole game much more fun and original than practically anything that can be done with 2k3.