Hi Julia,
Great to hear you are taking a trip to Portrush during your visit to Ireland. As you've already said, there is plenty to see and do in the Causeway Coast and Glens and I will try to give you a few pointers to make the most of your time here.
Having made the drive from Westport to Portrush a few times, in my experience the quickest route was: Westport - Sligo - Londonderry - Limavady - Coleraine - Portrush.
Some of the highlights in the Causeway Coast and Glens are the Giant's Causeway, a UNESCO World Heritage Site, Dunluce Castle, Carrick-A-Rede Rope Bridge and the Bushmills Distillery. If you are planning on visiting any of these locations it is worth checking them out in advance and also, in some cases, booking in advance. Of course if you are coming to experience the two beautiful beaches in Portrush, all you need to do turn up and enjoy the sea, sand and views! There are plenty of places to eat and drink in the town ranging from great coffee shops to a good selection of restaurants overlooking the sea and atmospheric pubs. There are car parks adjacent to both beaches.
For more information about the Causeway Coast and Glens please look at our website:
https://www.visitcausewaycoastandglens.com Have a memorable trip to Ireland!
Anne