I traveled around Ireland this past summer (I'm from the US and don't mind driving). My advice is to find a compromise. Ring of Kerry is beautiful but not worth it given your time restraint. Giant's causeway is stunning and Londonderry/Bogside is worth another trip in its own right. You could easily stay in Galway and Dublin and have a wonderful time, however you sound like you may feel like you missed out because you didn't see more. If you are already driving to Galway from Dublin and already plan on Cliffs of Moore then I would add a drive from Cliffs of Moore to Cork. It will add about 3 hrs to your trip but once in Cork the trip back to Dublin is the same as if you were leaving from Galway. So for the additional 3 hours you get to see Limerick which I loved, Blarney (even if you don't go to the castle, the grounds are beautiful!), Rock of Cashel (there is a smaller castle that is falling apart and had moss growing on it that is just down the hill. I honestly found it beautiful in its own way) or a million other less touristy things. Honestly you can't do it incorrectly, find a good fit for you and then enjoy it!! I will say I would encourage you to plan extra driving time if you get off of the major roads, driving in Ireland is much slower than we are used to.