Let me clarify, you CAN get an automatic, but they’re twice as expensive. And the three car rentals in Cork that we called were out of them (each only had a couple in stock.)
Newgrange was my very most favoritest thing. Kilkenny was nice; one of my favorite mid-sized towns with lots to see. Kilarney was the most beautiful of all the incredibly beautiful places we went. (About two days into our trip, I figured out why there are so many beautiful picture postcards of Ireland - you can’t trip over a sheep without finding a beautiful spot.) Not enough for a full day, but if you have time while you’re passing through, there’s a really neat butterfly farm and garden in Straffan. Tralee is great for theater, dance and music, whether you’re looking to be in the audience or maybe pick up a Bodhrian lesson or two. Cork was unlike anywhere else we went, with fabulous seafood and pubs.
If you decide to go to Dublin (and there are some great museums and gardens there), I strongly recommend going on a Sunday. The other six days of the week, it’s just like any big city in any country full of bustle and people not making eye contact. But on Sundays, everything suddenly slows down, and the street vendors and musicians and painters and sketchers come out, and it’s a charming, wonderful place.
Anywhere you go, pubs will be there. Make yourself at home, and they’ll make you welcome. As a girl, I avoided pubs on game days, but that’s probably not such a big deal for a guy - though it can still get crazy, especially in the north.) There’s very little tipping in most pubs (some of the bigger city ones are starting to expect it of Americans, because they know we do it here), but if your bartender is especially nice or helpful, the thing to do is to say, “And take one for yourself!” and pay him for an extra pint. He may drink one with you then, or he may save it for later (or he may not drink it at all, but understand that the extra money in the till is his to keep.) You don’t have to do this for every drink, of course. Just one or two during the evening will keep you on his good side.
Do use hostels.com or a similar site to find hostels to stay in. They’re perfectly clean and safe, and many of them even offer private or semi-private rooms. Most hostels we stayed at were around $20 a night, and most of them included some sort of inedible breakfast. Many of them have kitchens for you to use if you bring food. One of my favorite experiences there was cooking up a huge batch of American style pasta and meat sauce for about 30 hungry footballers in a hostel. Later on, they taught me how to handroll cigarettes, because Marlboros were just too damn expensive over there!