Itinerary Help

You will need an easy first day in Dublin to recover from jet lag.

Do Belfast as a day trip from Dublin - the fast train takes just over two hours to get there, which gives you a reasonable amount of time in Belfast (and probably more than you would get if you drove there from Westport....) Delete the night in Belfast on 9/6 and add this night to Dublin at the start instead.

I agree with your two choices of day trips from Dublin to the Boyne Valley (choose one that also includes Newgrange) and also to Glendalough. This can be linked with a visit to Powerscourt Gardens.

You can do Westport as a day trip from Galway - this cuts out a one night stand and is also less far to drive back to Dublin. Consider a stop at the early Christian site of Clonmacnoise stops at with its ruined chapels, round towers and carverd xcrosses. Other possinle breaks could be Athenry or Athlone.

Thank you for your thoughtful response!

This is the entire trip. We don't need to add a night into Dublin as we are there for five nights. We dislike having just a night in one place so I'm trying to figure out what to amend - skip Kilkenny and do two nights in Kinsale? I think there's a tour which will include Kilkenny. Is that enough? And what do do with 9/5 and 9/6? So close to getting this nailed down! Thank you.

8/25 - Dublin (arrival)
8/26 - Dublin (full day of sightseeing)
8/27 - Dublin (day trip: Glendalough/Belfast/Boyne Valley?)
8/28 - Dublin (full day of sightseeing)
8/29 - Dublin (Football game)
8/30 - Kilkenny (Kinsale?)
8/31 - Kinsale
9/1 - Dingle
9/2 - Dingle
9/3 - Galway
9/4 - Galway
9/5 - Westport (suggested, but I don't think we have time to explore this region). Replace with Belfast?
9/6 - Belfast
9/7 - Dublin
9/8 - Fly home from Dublin

"My challenge is spending 5 nights in Dublin!"
I'm not sure what the issue is (maybe cost?). You can certainly find enough to see and do to fill up 5 days in Dublin, but if you want to break it up, you could go to Belfast on arrival and stay there for 2-3 nights.
Glendalough is easily done on the way to Kilkenny, after you have picked up the rental car.
You could spend your last night or two in the Drogheda area. The Boyne Valley sites are quick and easy to reach with your own car. And you'll be on the right side of Dublin for dropping off the car before flying out. I can recommend an excellent AirBnB near Monasterboice, which is about 30 minutes north of the airport.

When you say Galway, are you also meaning day trips, perhaps to the Cliffs of Moher or the Aran Islands?

Do a Black Cab tour in Belfast, more valuable I believe than the Titantic.

Yes, Aran Islands and Cliffs of Moher for Galway.

Agree, five nights in Dublin is great. But we also want to see other parts of Ireland. I appreciate the input!!