How Long is Enough?

For your trips - somewhere between three and four months total time.

Since you are traveling with 3 different generations and want some rest time built in, I would think about 3 weeks with an apartment stay in each of your 3 locations. Perhaps a couple of one night stays at a cute b&b to break up your traveling to a new location transitions. This would give you an opportunity to see an outlying site that would be harder to day trip from a "home" base.

Get a paper map of Ireland or drop some pins in google maps of your desires and look at a route and base for all you want to see.

We only did the South with no rest days at all and we had 2 weeks. If you want to do North and South and have rest days, I would say 4 weeks

I would recommend no less than three days in each location. We did 10 days our last trip and there were no rest days which wore us out. We are going back in June and have booked 23 days this time. We have three houses with 4-5 nights at each, two hotels and one B and B. We have no less than two nights at anything and we are only doing two nights when the next day involves a short drive.

You could do your trip fairly easily with 15-18 days.

Thanks for everyone's input! I only have two weeks at the most, so we may have to decide what's most important to us, make those a priority and let some things slide.