Galway is always nice and lively and you'll have musical options to during the night, the Sweeney's Men reunion on the 15th should offer a bit of nostalgia for example. And it would probably be more efficient as a way of traveling, rather than go to Miltown and pop down and back to see Dingle (if you do decide to go Miltown-Dingle-Miltown, take the Killimer ferry across the Shannon instead of the long way round through Limerick).