Between Clare and Leitrim you can easily take up 8 days, especially if you take in Connemara, Mayo, Sligo areas. So resist any temptation to go beyond that region you don't need to. Perhaps if you fly into Dublin you might take a look at the city; of course if you don't you will "miss" things, but to do Dublin fully would take a month!
A couple of tips for the mid west. Unless you a very choosy you will find plenty of accommodation so you don't need to over plan.
2 great country houses - Strokestown & Westport - really deserve a relaxed half day each.
The Sligo/ Lough Gill/ Boyle region is full of archaeology which really rewards a little local advice and a bit of effort.
If you have a car - AND A GOOD MAP! - (michelin does well) your day will organise itself very easily. (If you simply SatNav the next destination you will miss the point of touring)