Ok-Dublin, Newry-Warrenpoint-Rostrevor-kilkeel-Newcastle (stop for food,plenty of choice). from Newcastle follow the coast through Dundrum,Killough, Ardglass, Strangford. Short ferry crossing to Portaferry. From Portaferry to Newtownards then Belfast. From Belfast follow signs for Carrickfergus then larne. From larne you follow the coast road to Cushendun, then take the Torr Head senic route to Ballycastle. Continue along the coast road to Ballintoy then on to the Giant's Causeway.
Things to see and do along the way-the Mourne Mountains at Newcastle(nice 30 mile loop through the mountains), good aquarium at Portaferry, Carrick-a reid rope bridge and Ballintoy harbour at Ballintoy-enjoy