In Octoboer, we will be flying to Paris for several days and then on to Ireland. We want to visit Dublin and County Cork. We will probably go back home (to the USA) from Dublin as I think it is less expensve, but should we fly in to Dublin from Paris and then take a train or bus to Cork? If so, then we'd be going back to Dublin to go home. Is there an easier (cheaper) way to do this?
You could look at booking your tickets as a multi-city itinerary - arriving in Paris, leaving from Dublin. Take a budget flight from Paris to Dublin. Bus to Co. Cork would be the least expensive option from there.
Fly from Paris to Cork. Fly home from Dublin. No backtracking. According to the search engine skyscanner.com, Aer Lingus is the only airline that flies directly between Paris (CDG) and Cork. While there is only one flight/day, booking well in advance will get you very reasonably-priced tickets.