We visited the land of 40 Shades of Green about a dozen years ago, celebrating our 25th wedding anniversary. I wrote about it extensively, offering suggestions and advice in another thread
started by a Roadfooder who was headed there in 2006. Hard to believe, but I was even more long winded then than I am now, so here's the summary as it relates to your stated itinerary:
Don't get a rental car until you're ready to leave Dublin. It will actually be a hindrance to you in the city. In fact, if Dublin is the only place you're visiting on the east coast, maybe take a bus to the west coast and rent a car there.
Unless you've got experience driving on the "wrong side of the road", you may want to relegate your time behind the wheel to daylight hours. Narrow, unlit, poorly marked roads are the norm in Ireland. Driving during the day is stressful enough. After dark it can be a horror show.
Your rental will probably have GPS. Even so, I recommend picking up a copy of Irish Ordnance Survey Complete Road Atlas of Ireland
. As I said back in 2006, "...The IOS Atlas is a highly detailed roadmap that may save both your life and your marriage. It will also give you great insight into nearby sites; historic, panoramic and otherwise. It is indispensable. It is also written in very small print; bring a magnifying glass."
A GPS will get you from point A to point B, but the IOS will show you all the fascinating stops worth making in between.
There are no straight lines in Ireland. It's a tiny country, but you won't get anywhere quickly, so don't even try. Slow down and enjoy the scenery, it's unavoidable.
If you're on a budget, eat a big breakfast at your B&B. Generally they're very good and very filling, eliminating the need for a big lunch. If you're primary goal is to try as many restaurants and pubs as possible, avoid the breakfast because you'll be full until dinner.
Twinwillow is right, the Soda Bread is quite good, but the Brown Bread is SPECTACULAR!
I think it's baked in peat fired ovens and picks up the most amazing aroma and flavor. We ended up asking most of our B&B hosts to skip the Soda Bread and just bring out the brown stuff.
Other food notes:
Can't speak for all of Ireland, but the fish and seafood on the west coast was fantastic. We enjoyed great chowders, lovely grilled and fried fish, and magnificent smoked salmon almost every day.
Responding to other comments above, we fell in love with Irish Dairy, but found the beef didn't deserve as much of a build up as it received. It was fine, but ordinary. Whereas the Dairy soared with rich texture and wonderful flavor. Wish we would've tried more lamb and mutton.
When in Galway, head over to McDonagh's Fish & Chips, the experience described in detail here
We ate most of our meals in the pubs. Very good food at reasonable prices.
Don't dismiss the restaurants located in petrol stations. We grabbed a very good Chinese carry out meal later in the evening when everything else was closed. It was a life saver, and damned good food to boot.
While at the petrol station, pick up a hunk of Irish Cheddar (or whatever cheese you like) and a packet of McVitie's Digestive Biscuits
. They make a great snack as you're traveling the road, or while settling into your B&B at the end of the day.
I'm sure more will occur to me after awhile, but that's enough for now.
Have a great trip!