It's only 220 miles from Dublin to Dingle, Jacqui, but one hundred of those are on a motorway. The AA (http://www2.aaireland.ie/routes_beta/) reckons you can do this in 4hr 20min, but that doesn't take into account the time of day when you leave Dublin and all manner of hold-ups that might occur on the way. I'd bargain for six hours.