Are there any Kona dealers in your area?

Blast

Fire Mountain

The components on these bikes aren't the greatest, but probably more than enough for what you're looking to do. I also got a really good deal on a 2005 Cinder Cone from my LBS, about $200 below MSRP just because they were looking to clear out some room for the incoming 2006 models. If you can find a 2005 Kona for a good price, buy it. The components are better than the 2006 models, and you might be able to find one at a discount.

I don't know if you've already committed to buy the craigslist bike, but these two Konas might be worth a look.