I'm realizing I still have some questions. One is: Although Dunguaire Castle is not holding banquets at the time we're there, can the castle itself be visited?
Mid April -Sept. - 9.30 am - 5.00 pm. You would probably need to send them an e-mail to find out when exactly they open this year (My guess around Easter)
it definitely opens the first of april. i have been by to check it out and called a couple of times.
also, as for the banquets and folk nights at bunratty, duguaire or any of those that the heritage center operates - they do add additional nights on demand. we were fortunate to get our family of 8 visitors into a folk night in March last minute and it was the highlight for my parents. we are looking at scheduling a departmental excursion to Dunguaire for one with my husband's staff and even the natives are looking forward to it.
having spent the winter (off season) exploring here on the west coast, we feel it is definitely worth it to go to the castles, ruins and historical sites even if they are not open. usually there are placards or markers explaining some the items and everything has been awe inspiring and educational. the views are without fail photogenic and memorable. our best discoveries are from just picking a road we have not been on yet and driving down it.
Thanks for the additional info. As I always tell everyone "nothing is written in stone in Ireland". Opening times are a guide but may not be adhered to. It is always best to phone ahead or make a quick inquiry of your lodgings hosts or a local tourist office to find out what is really going on. Yes, the banquets, Irish Night, etc. are "subject to demand". I'm glad you parents enjoyed their fun night out.
When you're in the area (or probably before you leave the States) you might want to check for high and low tide times. Dunguaire is much more photogenic at high tide. At low tide, it's surrounded by mud. Here's a site that does that: