Maporama.com shows the road maps for most of Ireland.
Zoom out and around from Portrush to see what route you want to take.
Coming from the South:
Follow signs to Belfast
Take M2 heading north
Take turn of for A26 to Ballymena/Coleraine
Take turn off for Portrush
Coming from the West:
Follow signs to Derry ...
Iarnrod Eireann timetables from Dublin to Belfast
and NIR timetables from Belfast to Portrush.
Bus Eireann / Ulster Bus timetables from Dublin to Belfast
and Ulster Bus timetables from Belfast to Portrush.
Street Map of Portrush.