Michael,
If I was you, I'd stick to the greater Dublin area. You have loads of good courses (Royal Dublin, Portmarnock, Portmarnock Links, The Island, Corballis, Laytown & Bettystown, Baltray, Seapoint) on the north side within 15-45 minutes. You could also try Howth GC. It's on the hill and the views are wonderful. Take the time to enjoy Dublin. Take the DART to Howth (grab some fish'n'chips with vinegar
and walk the pier) and Dun Laoghaire (walk to the end of the pier)
.You can get a train to Drogheda (from Connolly Station) and then a short taxi to Baltray (Co. Louth). As was mentioned, you could stay in the Dormy House and maybe play Baltray twice. Laytown & Bettystown GC is just south of Drogheda. You could get a taxi from Drogheda to L&B or get off at Laytown and get a taxi to L&B, or even a taxi from Baltray to L&B. The distances are very short.
Right next to Baltray is Seapoint. I haven't played Seapoint, but it's on the same strip of linksland as Baltray. It's not in the same league as Baltray, but I've heard it's quite good. That's three links courses close to Drogheda.
I think you should also consider Royal Dublin (shortish taxi ride), but only if you get the winter green fee.
Maybe the though of getting trains/DART and taxis sounds like a lot of hassle, but it's isn't as the distances and times are short and all the courses are close to the same line. The DART and trains generally adhere to timetables (it's the buses that are awful).