Plenty of salient and useful suggestions thus far. My own list of random bon mots in Leprechaunland:
Remember, golf is not everything. You've got to dive into the culture - there is no place quite like it in the world.
Read "Emerald Fairways and Foam-Flecked Seas" by James Finegan. Bring it with you on the plane because it is the best guidebook you've ever held in your hand.
Careful not to wear yourself out the first three days. The heaving dunes and fresh air encourage running full rip for 36, but that fourth day, it can be hard to get out of bed.
Cork is Liverpool without the Beatles, but don't miss Blarney Castle. I kissed the stone twice - but those reading my rants already guessed that.
The Ring of Kerry is like riding the last mule on the trail. All you see is ass and all you smell is shit. The busses are obnoxious - don't waste your time.
The Dingle Peninsula is the most beautiful place on Earth aside from Yosemite - and even then I am not quite sure.
Stop at the Inch Peninsula. It is the best piece of raw golfing land I have ever seen. Someday . . . . I prayeth.
Lahinch will be your favorite golf course, not Ballybunnion. Feel free to shriek, but it's the Prestwick of Ireland and I have no higher praise than that.
Stay at least three days in town. Play the Castle Course in the afternoon and take a short drive to the Cliffs of Moher.
Legend has it that ghosts beckon visitors to jump who venture too close to the edge. Don't do that - but bring your wedges. There is a lovely pitch & putt along the road back.
Dublin, Tralee and Kinsale have really good restaurants; the rest have greasy glop served by chain-smoking hags.
Killarney is a ridiculous tourist trap. Fisherman's Wharf (San Fran) with overpriced, itchy sweaters. Don't bother.
Old Head is so beautiful it looks fake. Good golf course, not great - but worth the time.
Make sure to stop by the Lusitania Memorial, it is a good reminder that WWII was really just an extension of WWI.
As hard as it is to find good restaurant food in Ireland, it is equally difficult to find bad food in a Pub.
No matter how quick and clever you think you are, that Irish guy or lass on the next bar stool can run circles around you. Craic is their national sport after soccer.
Remember, that beautiful and incredibly friendly redhead you're chatting up in the Pub knows you are an American. Don't even think about it . . . . . . she ain't buying what you're peddling.
When calculating driving distances, figure not more than 50 Kilometers per hour. Note, I wrote KILOMETERS - like 30 MPH. Driving on the left side of the road while trying to negotiate traffic circles - hemmed in by stone walls - is no time to play Speed Racer.