6 mature US adults (50-60 age) hiring car after 3 days in Dublin and driving south to Clonnmel for 3 nights. Want hints on good sights on drive day and then good day trips from Clonnmel before heading to Cork area for day and flight to London.
First, get the RS guide about Eire so you can get a feel of the country and what there is to see and do. Second, cut a day off of Dublin and spend it visiting Newgrange. Third, drive to Glendalough and through the Wicklow Mountains in route to Clonmel. From Clonmel easy day trips; Rock of Cashel, back to Kilkenny, over to the coast to see the Wexford National Wildfowl Preserve and, if you are interested, Waterford. Ireland is a small island. You can drive from Dublin to Shannon on the highway in 5 hours. West coast of Ireland is stunning. Could you include it your visit?
Also in the Clonmel area, near Rock of Cashel, is Cahir, with its castle in the river, and Blarney, which has beautiful grounds and a dolmen in addition to the castle (and good shopping, too). Near Cork are both Cobh (last dock of the Titanic), and Kinsale (cute little coastal town). I am a little concerned with your transportation arrangements. Will you have two (or more) cars? You might have difficulty finding a vehicle that will comfortably hold six adults and their luggage. You don't want to be driving with bags on your laps or around your feet.
We have 9 passenger van reserved, so should be fine. The 3 days in Dublin are the result of 2 of our party competing in the Dublin Marathon on Day 3, so we are staging and prepping them in advance. will take day trip from Dublin on day 2, but still looking for tips on where to stop and what to look for on drive from Dublin to Clonnmel.
I'm not sure what you are looking for. We have given you numerous ideas for things to see on the way from Dublin to Clonmel - Glendalough, Rock of Cashel, Cahir, Waterford, etc. There are different routes you can take, so different things to see along the way. It might help you to look at www.viamichelin.com to look at routing and where things are in relation to one another. Are you intending to stop for the night en route to Clonmel?