Dublin & Belfast: How might Ireland fit in to this Eurail trip madness?

Ireland has been a bit of a tough one, as far as planning and inclusion go. On the one hand, it seems daft to take a trip to Europe and not go to Ireland, north or south.

On the other hand Ireland, from my experience and from what I've heard from others, isn’t really a place where train travel is essential, or even all that beneficial for the traveler. And the point of this trip, blog, and all that, does focus on the rail experience.
That said, I could be wrong (though granted that goes for everything I say). Service may have grown and improved loads. Trains might now be a much better way to get around Ireland, though my own experiences a few years back never presented me with a route that Bus Eireann couldn’t handle, and for cheaper.
But I’m going to Europe, and I’m going to Britain, for malt’s sake. That, and the 10-person Celtic jam sounding out in front of me in Perugino has me thinking about Ireland like I haven’t since trad seshes in Galway’s The Crane Bar. (Perugino also has bottled Guinness, to get some proper Oirish representation amongst the Belgian beers.)
At the least, Dublin should be in order. I can take the ferry from Fishguard, Wales. Could I get to the west? Is it feasible, or a good idea, for this trip (and not just for my Aran Islands soft spot, mind you)?
I don’t know yet. But at the least, Dublin… and sure, Belfast. If I’m already there, after all, plus I can take the ferry from Belfast to Stranraer, near Glasgow, to start the the Scottish leg of my UK trip.