We travel very regularly the Republic and Northern Ireland. Definitely Camac Valley for Dublin. There is a red tourist bus that goes at one time but it does not take dog, however it is cheaper. Other buses are more regular but they’re not always on time. You can pick up a timetable in the reception. Book early if you’re going in peak season, as it gets very busy.
We mostly wild camp. Definitely join motorhome craic. Great app and forum, with helpful members (got a us out of trouble a couple of times) as well as the POIs which will tell you about water, launderettes et cetera. If you are stuck somewhere, go for a meal in a pub, they will nearly always let you stay overnight in the car park. Lots of harbours have free water. Carry a watering can and perhaps another water canister. You should be seen to be only taking a little water and not overdoing it with a big fill.
In the Republic, getting rid of rubbish is a problem. There are no public bins. Just occasionally a very small ones where you would have to feed rubbish bit by bit. And they have clear signs saying no domestic waste. Take some large thick black sacks so you can pack your kitchen bin bags into the large sacks. And place in the garage! We booked onto a campsite every now and again to get rid of the rubbish. You can take the rubbish to the municipal dump and pay to dispose of it but these seem to be few and far between.
Enjoy great country and great great people