Dublin: Anything NOT on RS Tour That You Wish You'd Seen

One suggestion would be to visit Howth. Northeast of Dublin, on the coast. A delightful seaside village. Nice restaurants near the harbor, relaxing pubs. And nice walks along the hills and cliffs with lovely views of the sea, Not overly touristy! Would be a leisurely afternoon and dinner. Back to Dublin by early evening.

Easy to get to via DART. Just take the DART train marked Howth - the final stop. Probably about 30 minutes from Dublin Connolly station.

We took the RS' Best of Ireland Tour, and arrived a couple of days early. We spent time at the EPIC Museum (Irish Emigration Museum), which I really enjoyed, but I love history. We also visited The General Post Office, site of the Easter Uprising. On our tour The Kilmainham Gaol was included, also another important historical site.
To me Ireland was all about the "sessions" in the local pubs, so that would be a fun way to spend an evening.

When I was there in 2013 I took a local bus tour to NewGrange and Tara Hill. I think I found it in the RS guidebook at that time. I do remember that it was important to be sure your tour included a time to actually get into the site at NewGrange because access is limited.

Anyway, I really enjoyed it and thought it was fascinating and tourist money well-spent.

Also, the first day I was there I got on the Hop-on-Hop off bus and just rode all around the city (not hopping off ;) It was a great way to get a feel for the city and where everything was. It also happened to be an absolutely gorgeous day which was a bonus!
You will love Ireland no matter what the weather! Enjoy!

Having just returned from a RS "Best of Ireland" tour I can personally recommend Mary Gibbons day tour to the passage tombs at Newgrange and Knowth (includes the Hill of Tara also). I took the tour prior to joining my RS tour since this site is not included on the itinerary. You can book on Newgrangetours.com and pay for it in Euro on the day of your tour. I am so glad that I did not miss seeing this UNESCO World Heritage site. It was amazing! You will love Ireland....such a beautiful country and the people are so welcoming.

One suggestion would be to visit Howth.

We did a 12 day tour with another company. Prior to it starting, my husband and I took the train to Howth to hike the coastline and have lunch. It was my favorite day in Ireland (out of about 18).