With the narrow streets, the traffic was very congested every place we went in town and at every time of day. Not to mention, they drive on the opposite side to what we are used to in the USA, which made even crossing the street on foot interesting, to say the least.
Its not that far to anywhere, and I'd really suggest you plan to walk almost any place you need or want to go in the downtown area! And be sure to use the crosswalks!
Theres loads of tour buses doing the ring of kerry, most running out of killarney or cork. The roads can get conjested!