Just my 2 cents: March weather can be notoriously fickle in all of Ireland and especially Cork. Spring will still be just a distant promise so you'll be dealing with cold temps, short days, and a lot of rainy conditions. Point being that you might want to consider throttling back on your pace bit to allow for those days when doing much of anything outside really won't be an option.
Personal opinion only, but I think 4 days in Dublin is a day or two too many. A couple of days in the city will be enough to get over your jet lag and generally satisfy your curiousity about the place.
Rather than using up most of another travel day just getting from Cork to Galway, my suggestion would be to base yourselves in the vicinity of Killarney for a few days - long enough to enjoy the National Park and the Ring of Kerry. Dingle would be only an hour away, making a day trip there much more doable than trying to do it from Cork. And if you'll have a car you could explore the beautiful Skellig Ring road with a stop at the Kerry Cliffs, as well as enjoying a few hours at the Gap of Dunloe - one of the prettiest little glens in Ireland.
Personally, I'd devote the majority of my time to the west of Ireland, ie Dingle and Kerry, rather than trying to make it all the way up to Galway this trip.