Some years ago - i.e. before I became a compusive recorder of routes - I had an excellent week cycle-camping in Eire. It went roughly Dublin Airport, Mourne mountains, Kells, round the coast of Kerry, round the Dingle, Doolin (which I knew from caving), over the Burren, Galway and back to Dub on the train.
The interior is very pleasant rural limestone scenery but all fairly similar. I preferred the coast.