I just traveled to Ireland in April with a similar itinerary:
Day 1: Dublin;
Day 2: Dublin;
Day 3: Dublin to Galway (stopping at Trim Castle and Athenry)
Day 4: Cliffs of Moher, Limerick, Dingle
Day 5: Dingle
Day 6: Killarney, Cobh, Enniskerry
We opted for Dingle rather than the Ring of Kerry. We also flew in and out of Dublin.
Day 4 was long for us - got to the Cliffs around 10am, Limerick around 1pm, and didn't arrive in Dingle until 6pm. Also, Day 6 was long, with lots of travel to get back to the east coast (in order to catch our flight the next afternoon out of Dublin).
Day 5 looks like it may be too much. Driving from the cliffs and doing the entire drive of the Ring of Kerry seems like a lot, never mind adding Killarney too. Depending on when you land, perhaps stay two nights in Dublin and give yourself another night in or around Kerry.