Chateau Lagorce is a 30 minute drive from Bordeaux city airport on good roads and it is a lovely drive through vineyards once you leave the motorway.
Aer Lingus fly from Dublin to Bordeaux once a day 6 days a week, with Tuesday being the only day that they do not fly.
Ryanair fly from Cork to Bordeaux twice a week on Tuesday and Saturday.
Cityjet have recently announced new flights for Cork to La Rochelle which is a very popular seaside town that is 2 hrs drive from the Chateaux.
Getting the ferry over from Ireland is very easy with sailings from Cork, Dublin and Rosslare. It might seem expensive but when you work out the cost of flights together with car hire, and then the savings you will make by stocking up on wine on the way back it actually works out ok in terms of price. If you do decide to go by ferry then be sure to book early as they fill up very quickly.
Driving in France
Driving in France is ok and actually not too stressful because there's an excellent motorway and rest stop network. The motorway tolls can add up however. The Via Michelin website is an excellent resource and definitely worth consulting when planning your trip.