Dublin has an excellent position for exploring Ireland and countries beyond.
Ireland, at 300 miles in length and 170 miles from east to west, is a small enough nation that it’s possible to drive from coast to coast in a single day. This is not to say that it’s advisable to do so: one serious mistake is to look at Ireland’s National (N) roads with a US "mile a minute" expectation. These ain’t Interstates: most of them are two lane affairs, without any shoulders, which creep right through the narrow center of any town on its route. While dual carriageways (four lane highways) and bypasses are gradually appearing along many routes, don’t plan on making any more than 30 or 40 miles in an hour of cross-country driving. Seriously: take things at the Irish pace, for your vacation, and enjoy the scenery.
Renting a car, of course, lets you decide where and when you want to go. It will also allow you to see many places where a bus or train doesn’t run. In general, the companies here will rent cars to fully-licensed drivers between 25 and 75 years of age. Goireland.com, Ireland’s National Tourism Service claims to find the lowest prices on rental cars for tourists--- may be worth a look. Oh, and there’s a couple DFA tips to know for driving over here, too. Check ‘em out.
If you don’t feel like shelling out between £30 and £300 per day, go ahead and take the bus or the train. Both modes of transport are managed by the same semi-state body, the CIE. Much of the country is covered, and the prices aren’t all that dear. Dublin Bus is also run by CIE--- it will take you to almost all points around the capital. Don’t expect high-class, but as public transport, Dublin Bus is better than any service I’ve seen in the States.
While hitchhiking is safer than in the US, I wouldn’t recommend it. I’ve seen a bunch of backpackers with their thumbs out down in Kerry, Clare, and Galway, but it’s quite uncommon in the rest of the nation. A couple years ago a hitchhiker named JoJo Dollard was picked up by the wrong sort of fellow, and that’s more or less scared the practice out of the country. So, do take the bus or train instead.
The best way to get from Dublin to the UK or to the Continent? Fly in style, baby. Over the last couple of years, a number of budget airlines have been competing flight prices into the spare-change category. This has forced Aer Lingus to lower their fares. My mate Ken got two return tickets to Edinburgh for 37p apiece- no joke! Landing fees and other bullshit jacked the price up to £20 or £30 apiece, but that’s still dead cheap for an International round-trip flight. I got myself two return tickets ("return" means the same as "round trip," by the way) to Glasgow for £70 total. We’d have spent more than that on petrol, for a weekend getaway down the country. Not too shabby!
One word of warning, on the subject of budget airlines:
Don't be fooled by their lies about incredibly cheap seats. It's a lure, you'll wind up scammed and stranded. Heroin dealers have more integrity and concern for their customers' wellbeing.

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