We had 8 days and nights in country. It was me and a 13 yr old, so I decided to skip Dublin. This was what we did:
Day 1: Arrive 7 am in Shannon; drive to Rock of Cashel, Cahir Castle, stay at Ballyglass House
Day 2: Drive to Dingle with a side drive through Ring of Kerry. This was the only day I thought was TOO MUCH. If you're doing Dingle peninsula for a few days, Ring of Kerry is miss-able. We did love the stone ring forts tho. Stayed at Greenmount House.
Day 3: Dingle; Stayed at Greenmount House. Did the Tim Collins tour. SO WORTH THE MONEY!
Day 4: Dingle; Stayed at Greenmount House. Did a harbor tour. Meh. It was fine for what it was. But not fabulous.
Day 5: Drive to Galway through Adare; Stayed at Petra House
Day 6: visit Aran Islands (with John Faherty's Aran Island tour that leaves by bus from Galway); stay in Galway; Stayed at Petra House
Day 7: Visit Connemara and Kylemore Abbey (via Galway Tour Company by bus); stay in Galway; Stayed at Petra House
Day 8: Drive back to SHannon, via Dunguaire castle, Cliffs of Moher and the Burren drive in Rick Steves Guide. Stay at disgusting Park Inn right by airport.
The only think I would have done differently is skipped Ring of Kerry and skipped Connemara if it was a really rainy day like it was when we went. I'm sure Kylemore is lovely and I know the gardens (I'm a gardener) would have been amazing if it hasn't been raining horizontally). As it was no amount of umbrella, raincoats and waterproofed shoes made a difference. It was cold and miserable. I think the length of a western Ireland trip was exactly right. Anymore time and I think we would have needed to go to a different region not to get bored (Northern Ireland for a few days would have been awesome).
Other details:
Our rented car was from Dan Dooley. Buy the super expensive, super extra expensive insurance coverage. Ours came in handy within 3 hours of getting the car when I scraped against a 2 foot wall on the left during a turn that I couldn't see. I'm actually a pretty good driver and the driving on the left didn't bother me too badly, but the roads are really really tight and it was nice not having to worry about any problems with the car.
Ballyglass House--I'd stay there again. It's an older home and not updated, but the rooms were warm and comfortable, best hot good pressure shower I had the whole of our stay in Ireland. Food was good, not great. Price was right.
Greenmount House--HIGHLY RECOMMENDED. Very luxurious, quiet, gourmet food (best food we ate all trip. seriously.). Gary was fantastic with recommendations for restaurants, pubs and so forth. I will dream about this B&B for years to come. I already have fantasies of going there for like a month in summer and just being.
Petra House--Very clean, nicely updated, good food. Frank is very nice. Very reserved but very helpful when you ask for recommendations for food and tours.
Radisson Park Inn by Shannon Airport--people, this is a hole. They are refurbing, but I'm reasonably certain we had a refurb room and it was gross. The kind of gross where you need to make sure your legs don't brush against the bedskirt and you wonder if you're going to get bugs.