HI from Wisconsin,
If you are not into very touristy...then you better skip Killarney. I have been around the entire coast of Ireland and crisscrossed the country many times. Killarney is the most touristified of all of Ireland. Killarney's Black Valley is nice, the city is horrid. And Kinsale has moved up the list for tourist visits. What was once a nice fishing village is now jam-packed with tourists. The forts nearby are of interest.
I do like the limited number of miles your plan suggests. Here are two suggestions. Just north of Dublin is the Boyne River Valley. Now it does contain New Grange a major tourist attraction. But the river valley is lovely and whether you go toward Drougheda to see Saint Oliver Plunkett's head or up stream to some nice vistas and small villages along the way. You can have a very Irish day trip. Trim, Hill of Tara, Slane, Navan, and Kells with its crosses. Trim castle is a bit further and maybe this can be an overnight.
South of Dublin is Glendalough. Again a tourist attraction with a car park big enough for busses. But the Wiclow Mountains are wonderfully wild. Druid Glen is nearby. Cut across to Kildare to visit St. Bridget's. A bit of a drive further, maybe an overnight so you can go slow is Abbeyleix with Morrisey's Pub, one of the best traditional pubs in Ireland and serves an excellent pint of Guinness.
When I look for non-tourists areas of countries I take their nation-wide tourism book (Fodor's, Fromers, Rick's book) and look for the counties that aren't covered. And I go there.
As always, Ireland should be sipped, one pint at a time. Slower is better. Ask for "a slow pint of Guinness, please." If ppoured correctly, it will take 4 maybe 5 minutes to get it. You'll think they forgot, but they haven't.
wayne iNWI