I have booked rooms in Portrush and wish to stay the next night in Cong, just a little north of Galway. It appears that the drive will take between 6 and 7 hours from the maps I have. If you have first hand experience with this drive, I would appreciate your comments.
We did this drive last year in the opposite direction, but in a leisurely fashion. We stopped in Sligo for a while and overnighted at a B&B near Enniskillen. Had we done the drive non-stop, my guess is it would have taken at least 5 hours.
We also did this drive in reverse. From Cong we overnighted in Dongegal before heading on to Ballycastle on the Antrim Coast.
Sorry, I have not made this drive, but I have to put in my 2 cents in regards to Cong. We just returned from Ireland a couple weeks ago, and I think Cong was probably one of my favorite villages--and we went a lot of places--put 2000 km on the car. We stayed at the Lydon's Lodge which had a really cozy pub downstairs with a peat fire going in the fireplace. There really is a lot to see there (as stated in "RS Ireland 2010"). Take the nature walk behind the abbey, if you keep going you will come up the back way to Ashford Castle. Otherwise, just take the 15 min. walk along the main road to the castle. Another village we stayed in the Connemara region was Clifden, and it was really nice too, but Cong is really quaint.