We will be traveling to Ireland in May, '22, wish not to rent a vehicle, and to go by train or bus from Dublin to Ennis, near Limerick. Would appreciate your thoughts re: both modes of transport, especially in this era of COVID-19
My husband and I were there in October. We took the train from Dublin to Kilkenny and back and had no problems. It was exactly on time both ways and very comfortable. I would take the train, not a bus, as buses take longer and have more stops.
We also took a day trip out to the Cliffs of Moher + Doolin with James who owns Ireland Chauffer Vacations. He operates out of Kilkenny but offers day trips around Ireland and multi-day private tours. Great guy, fun to talk to and gives you a real local perspective of Ireland. And he's very flexible so if you need a transfer to your next hotel after your tour you can arrange that with him. Highly recommend him! Overall we are glad we didn't rent a car because riding with him we saw just how narrow a lot of the roads are and got to enjoy the scenery as passengers.