Hello there. Your itinerary has many of the same stops that my husband and I along with our two teenage sons followed on our memorable two week trip in late June early July in 2017. (But in reverse). Much of what we did came from this very site! Here are my thoughts on it if that helps you with your planning.
We did Dublin-(2 nights) then rented a narrowboat barge for 3 nights and slowly went up the canal from Vicarstown (Barrowline Cruisers and no boating experience necessary-I have a report on it on this forum to which I have copied a link below) drove to Kinsale and spent only one night. We got up and visited the fort the next day and then drove onto Kenmare where we spent 2 nights. Kenmare has a nice little beach just outside of town that we walked to from our inn.
We did the Ring of Beara (based on comments from this forum) the day after arriving in Kenmare and it was one of our most favorite parts of the trip. Definitely go into Gleninchaquin Park on the peninsula (http://gleninchaquinpark.com/), we had the whole place to ourselves. Stone circles, a waterfall, trails for walking. It was just lovely. We drove in for quite a while on a small road and thought we might be in the wrong place but then we saw the views and some signage. We cut across to Castletown/Bearhaven and then up the back side. There is a really cool castle just outside of Castletown, worth the visit. (O' Sullivan Beara Castle) The ride back to Kenmare from the other side of the peninsula was thrilling but beautiful.
We then went on to Dingle for 2 nights followed by Liscannor for one night for a visit to the Cliffs of Moher. (We parked at a private farm which had parking for a small fee and walked along the trail to the visitor site.) We also took the ferry at Tarbert and it was easy and quick. We lucked out and drove up as it was loading up but they do go back and forth quite often. My husband enjoyed the break from driving.
The drive to Clifden from Liscannor with a stop in the Burren was a bit of a long day for all of us but it was the only day that felt truly tiring. Clifden is beautiful and the drive through the mountains is breathtaking.
We then left Clifden and drove to Shannon where we spent one night near the Shannon airport and flew out in the morning (so easy)
We decided to skip the Rock of Cashel (again, to avoid crowds) but did go to the Castle of Cahir which was not crowded at all and it was a beautiful location and a pretty town. We loved that we could walk around the castle and go up into the towers at our leisure.
There is not much I would do differently and it was nice to have 2 nights in most places. Kinsale was my least favorite town as it was overrun with busses and tourists (although the ghost tour that RS recommends was fun and the fort is amazing!)
Our most memorable hotel was in Clifden and I highly recommend it, it is the Quay House and it is on a little bay. Amazing rooms, owners and breakfast. Our B and B in Dingle was lovely too, a short walk to town and probably the most delicious scones and crepes I have ever had. (Brambury's Guest House)
Also...I learned that you could drop off a load of laundry at the cleaners in most of these towns and then pick it up the next morning washed, dried and folded for about 15-20 bucks. That was really helpful for traveling light! (not sure why I never thought of that before in all of our traveling)
Sorry this is so long, hope it helps.
Here is the link to the boat report:
https://community.ricksteves.com/travel-forum/ireland/narrow-boat-barging-in-ireland-an-amazing-experience
