Ireland!

Mags • Veteran & military spouse. Obsessed with our dog and our cat is an asshole.
My husband and I are planning our honeymoon finally!! (A year and a half after the wedding...)
He will just be getting home from the Middle East and I will just be completing my semester for school, so Christmas in Ireland it is!!!
We're hoping for baby dust over the 15 night stay, but regardless, does anyone have any insights as to Dublin, Sligo, and Galway in December?
Must sees?  Places to avoid because it's December?   We'll have a rental car and plan on driving all over!
I'm beyond excited for this!!!!!