Originally Posted by
noniron
Come up 'North'!
A very easy 2 hr drive takes you Dublin-Belfast.
Take a day and night in Belfast, then tour up the North Coast of NI with a night in Bushmills and a coastal lap of Donegal over 3 days, just fabulous in May!
So many very pretty towns and villages to pass through and stay in, a lot less 'touristy' than doing the Dingle thing.
The OP limited his trip to 4-5 days and indicated a strong desire to go to the Cliffs of Moher. Without those limitations, I'd second your suggestion. I've done Northern Ireland on every trip since 2010 and wish I'd gone earlier--the scenery is as fantastic as it is in the Republic but there are fewer crowds. EDITED TO ADD: And, having seen both, I believe that the Giant's Causeway is every bit as spectacular as the Cliffs of Moher. Given the parameters of the OP's trip, he'll have to choose one or the other though because the amount of driving needed to go from Dublin to Belfast to the Giant's Causeway to the west coast down to the Cliffs really is more time in a car than I'd prefer to spend with 4-5 days in Ireland/NI.
And while Dingle/Dingle Town may be touristy, it's still less so than Ring of Kerry/Killarney.