I'm part Irish (Patrick Carroll Reilly) Made it to England and Scotland but not to Ireland. I went by myself in 1999, rented a car and drove all over for two weeks. Did you just decide to go? Rented bikes, license requirements? Looked like a blast!
It was a blast ! A couple that we ride with went there a couple years prior for their sons wedding . He kept telling me how it would be an awesome place to ride. He wasn't kidding. Your regular U.S. drivers license is all you need. I can't recommend the trip enough.
