Looking for recommendations/suggestions for where to spend our 2 extra days after our RS 14 day Ireland tour ends in Dublin. RS book says something about taking the ferry to Wales. Is that do-able as a day trip?
I think you're looking at p. 96 in the Ireland book. The faster boats take 2 hours each way Dublin-Holyhead and run just a few times in each direction. But then it would be another hour each way by train to a destination like Conwy, for instance.
Since your tour doesn't include Bru na Boinne and Newgrange (chapter starts p. 108), I'd give that top priority for one day trip.
Are you going to have any days in Dublin ahead of the tour? I agree with Laura about Newgrange and Bru na Boine for a day tour. These sights were amazing.
I haven't been to the other places mentioned, but there certainly is a lot to see and do in Dublin. From my reading of the itinerary, you only have one day in Dublin. Dublinia is a hands-on Viking experience, fun and educational. Kilmainham Gaol is highly recommended (get there early, tickets are on a first-come, first-serve basis and run out), the Archaeology Museum is excellent, the evening Literary Pub Crawl is a great tour, and also do your own crawls through Temple Bar, live music afternoons and evenings in most of the pubs, which are fun to explore. There's lots more . . .
I don't see Glendalough nor Powerscourt on the itinerary . Stay in EnnisKerry at the Coolakay B n B if there's room. Enjoy the scenery and the quiet.