There are halls in UCD but a lot of students rent a room with a meal a day from a landlady, at least for the first year. Cousins of mine from outside of Dublin all did this and had 6 meals a week, comfortable, clean bedroom, sometimes bathroom ensuite but sometimes shared with the landlady, sometimes with babysitting arrangement with landlady's children occasionally to offset against cost. A lot of students rent a house with others too -- friends of mine lived in the same (fairly bare bones) 3 bed semi that their parents had bought for the purposes of student accommodation/investment. All the family in turn lived there with other students paying rent, fending for themselves food-wise and were occasionally checked on by the house owners to make sure heat was on, oven working, fixtures ok, house not too much of a pigsty. There are also houses and flats rented out by landlords to students allover the city and burbs. Rathmines, Rathgar, Ballinteer, Stillorgan, Booterstown, Blackrock, Clonskeagh are all quite close to UCD.
Buses traverse the city and suburbs, enabling students to commute from further afield, whether from north, south or west. Unfortunately, UCD isn't on the Dart unless the student is willing to leg it from Booterstown, quite a hike esp in wet/windy typical weather
One great thing about UCD English is that it is three years start to finish. The other great thing is that it is a really good course. UCD has a very vibrant student life and Dramsoc, L&H, LawSoc, etc., (latter two debating societies) -- in fact the Socs in general are all great ways to get into the swing of things. Lots of student publications...