I am looking forward to the day when Rock Steve puts together a tour of Northern Ireland. I would love to see the Giants Causeway,
The 14 day Best of Ireland includes two stops in Northern Ireland, and the itinerary includes the Giants Causeway. You can always stay longer on your own.
Northern Ireland is fairly accessible by public transport. You can take the train and then a bus and be at the Antrim Coast/Giants Causeway. My favorite hotel in this area is the Bayview Hotel in Port Ballintrae. The bus from the train station stops right outside the hotel. From here, one can walk to Giant's Causeway, Dunluce Castle, Bushmills and even Port Royal. If you don't want to walk, the same bus will take you to all of these spots.
I agree that there are enough places of interest for a tour in Northern Ireland.
Very easy to do it yourself. I did. I stopped in Londonderry, Portrush (where I had the best Guinness at the Harbour Bar), and then Belfast. Saw the Giant's Causeway as a day trip from Portrush. Northern Ireland is well worth seeing. The people are VERY friendly and you leave the tourists behind. All of it is very easy to do by bus.
Northern Ireland is included in the BOI Tour. We stopped at the Giants Causeway, had a local guided tour of Dunluce Castle then a local guided tour of Londonderry the next day. Stayed the night in Portrush just after the British Open had concluded and then traveled on to Belfast, with another local guided tour and then a visit to the Titanic museum. Great part of the trip, only complaint was the horrible food in the very British town of Portrush.