Kirkuk isn't all that big, but it sure doesn't hurt to have your own transportation. It's more convenient... Plus, my new ride happens to have functioning air conditioning and a stereo ; )
There are buses on base as well.
If you notice the flame in the background, it's natural gas burning off of an Iraqi oil well.
I had a very long trip to Kirkuk. There was enough to write about it that I can't possible scale it down to the 2047 characters I'm limited to in this Tips section. So, the rest of this tip will be in my Travelogue entitled "Germany to Kirkuk, the Military way..."
* If you have a choice, make this trip on a commercial charter ; )