Rent a small car, drive on the left, and take the insurance seriously

Outside Dublin, Ireland is best seen by car, and the roads are narrow with stone walls close on both sides; rent the smallest car you're comfortable in and take the collision damage waiver, because the excess is large and the walls are hard. Drive on the left, give way on single-track lanes using the pull-ins, and expect sheep. Many credit cards' rental insurance excludes Ireland; check before you decline the counter's cover. The Leap card covers Dublin's buses, trams, and DART trains.