Travel in the Countryside

There are 4 general categories of roads in Ireland: "M" roads which are divided highways (known as dual carriageways); "N" roads which are national roads with at least one lane going in each direction with those near the larger cities being divided; "R" or regional roads; and "L" or local roads. I'm assuming you are concerned about the smaller "R" and "L" roads. They can be quite narrow, twisty and bounded by walls and hedges. If they are less than 2 lanes wide they will have turn outs so that cars travelling in opposite directions can pass each other. If travelling between Dublin and Limerick, for example, you will be mostly on M and N roads. But if you want to see the countryside you will need to be on at least the R roads at some point.

You can preview specific road conditions by using the Street View feature on Google maps, which we've always found to be quite helpful before setting out for a day's driving.
Comes in really handy on the R and L roads as Trotter describes.

Driving along R and L roads is slow especially if there is slow moving traffic in front of you. Overtaking isn't easy and you have to learn to be patient. Be aware of other traffic and do pull in to the side to let a queue of traffic behind you go past.

As far as condition, I thought most were in good repair. Once off the main roads I didn’t think the signage was all that great and not always easy to see. If you happen to be on one of the one track/lane, 2-way roads, you need to keep a watch for the pullouts in case a vehicle comes from the other direction.