We rented a car (first time for me driving on the other side of the road, and with a manual stick that I hadn’t done for over 25 years). We drove the 3.5 hours over to the Cliffs of Moher. It was worth it. We planned stops along the way. There is actually a gas station with a museum dedicated to Barack Obama in Moneygall that you can stop at and see.
Also you can hit some castles out there. It really is a beautiful country!!
I would also recommend Kilkenney castle which is another 1.5 hour drive.
We didn’t do much in Dublin itself but only because we didn’t have a lot of time.