lwildernorva

This is my personal view but backed by a dozen trips since 2000 and a bit by my experiences traveling with others: unless you're a city person, plan no more than two or three days in Dublin and then spend the rest of your time around the rest of the country that you can reach. I really like Dublin, and I'm not saying you'll see everything you want to see in two or three days, but you can see most of it, and you'll understand after one trip there that there are two Irelands--Dublin and the rest of the country. Dublin is a modern city with a lot of history and a solid literary background. But no one I've ever taken there, all first timers in Ireland, needed to spend more than three days seeing the city and hitting the pubs at night, and in one or two cases, my fellow travelers have said that Dublin was their least favorite part of Ireland.

Since you like music and breweries, you should look at musical pub tours of Dublin and check out the Guinness and Jameson tours. I very much recommend Guinness, even if you don't like the product, for several reasons. First, the tour is totally self directed, which means that you can shrink or expand your time there to fit the rest of your schedule. Second, there are aspects of the Guinness experience, such as their long advertising history and their presence in Dublin for so long, that I think can be interesting in and of themselves. Third, the view from the Gravity Bar at the top is one of the best views of Dublin and the Wicklow Mountains. Jameson is worth several hours, but there, you're part of a tour group and must apportion time for that. Phoenix Park is a huge public park on the north side of town--twice the size of Central Park. St. Stephen's Green is a much smaller, in-city park that you easily walk around in less than an hour, but it's very pretty and a good place for a picnic lunch. Dublin Castle is probably worth a visit, but don't expect a classic castle experience. Since Ireland was neutral in WWII, you won't see much about that, but Dublin was central to Ireland's eventual independence from Great Britain, and there are a number of sites related to that time. Dublin is also an improving restaurant city and a city with a good theater scene.

Once you're outside the city, you'll have to pick and choose because as you have already said, you don't have enough days to see the entire country. Most visitors want to go to the Ring of Kerry in the southwest, and there's no doubt that the scenery is spectacular. Killarney, the unofficial capital of this area, mostly because of its congregation of touristy chain hotels, is a natural starting point. But I have gravitated to the nearby Dingle Peninsula because it's not yet overrun with tourists the way the Ring of Kerry is, and Dingle Town is far less touristy than Killarney although the prices at some of the restaurants are sky high as you'd expect from a well-traveled tourist haunt. In either case, either join one of the bus tours or if you drive, prepare to spend most of your driving time behind one of the tour buses. Each of these coastal routes is a narrow, twisting two-lane road and you're only likely to get around one of the slow-moving buses when they choose to pull off at a viewing point or one of the tourist trap stops they'll make along the way. If you work your way up the western coast, you'll come upon another popular tourist attraction, the Cliffs of Moher, which is a spectacular site but also a place overrun with tourists.

Galway, on the west coast, is a good pub town, but on a visit this past September, my group liked Cork , in the southeast, much more than I would have expected. Conversations with locals revealed that because of urban improvements around Cork, it's probably a better place to be than it was 20 years ago. Killarney, Galway, and Cork are all within a couple of hours of Dublin on the hub-and-spoke road system that features motorways all leading to Dublin. Keep in mind, however, that driving around the rim of Ireland between towns like Cork and Galway, you won't see such great roads. Many of the major rural roads in Ireland, called National or N roads, are no more than two-lane roads that can be a terror to drive the first time and especially after dark. BTW, since you plan to drive in Ireland, it's a good idea to get familiar with this thread: Car Rental Insurance in Ireland -- Very Confused. The TL;DR version: don't assume that you can stroll up to a rental counter in Ireland as you would in the US and waive local insurance so you can rely on insurance offered by your credit card. You can use insurance afforded by your credit card, but it's almost certain the rental car company in Ireland will require written proof of the coverage afforded. That thread covers that issue and more.

In addition, the "drink driving" laws as they are called in Ireland and other parts of Europe are much stricter than in the US and just recently became stricter with an immediate three-month ban (for local drivers) if found to be over-the-limit. Combined with the quirks around the roads, I'd advise being able to walk between your accommodations and any pub or restaurant you visit in Ireland.

If you really want an off-the-beaten path experience, going up to Donegal in northwest Ireland will take you into the most unspoiled part of the country. The towns are smaller, and you'll find more signs and spoken language in Gaelic than in any other part of the island. If you go there, however, the nearest spoke road back to Dublin runs from Sligo, and it easily takes several hours to get there from the far reaches of Donegal. You may not have enough time to get to the southern parts of the country if you choose to go up there.

One more BTW--don't overlook Northern Ireland. It took me ten years before I made my first visit there, and I'm sorry I waited that long. First, the bad. I think the people in Northern Ireland are far more reserved (less fun?) than in Ireland. I've warmed a bit to Belfast, but if Dublin isn't worth more than three days, Belfast isn't worth more than two. But the good is wonderful. The scenery is every bit as fantastic as in the Republic, the train trip from Castlerock to Londonderrry is one of the most spectacular in the world (and runs through a tunnel underneath the Mussenden Temple, which my friends who love Game of Thrones tell me has played a role in that series), and the Bushmill's distillery is definitely worth a visit. If you decide to go to Donegal, it's easy to get to Northern Ireland at this point although the potential for a hard border between Ireland and Northern Ireland is a real, possible side effect of Brexit. Right now, crossing the border between the two is like crossing the border between two states in the US--a road sign marking the border is about all you'll see--but that could change.

And a final BTW, although you've asked more about Ireland, I think Scotland is worth more time than the five or six days you've apparently allocated for it unless you've been to Scotland before, and this is your first trip to Ireland.