The hike itself is not easy, but not super hard. My wife and I took our two daughters (4 and 8) and they handled the hike just fine. There's a few areas where they needed some hand holding, but nothing much to worry about. The monument for the Long Woman's Grave, seen below, is in the parking lot at the beginning of the hiking trail, so it requires no hiking.
The hike took us about 80 minutes to reach the top (and again, the trail continues for several kilometers all the way to Carlingford). We stopped when we reached the large cairn of stones at the peak of one of the mountains.
The view from this peak was absolutely amazing!
At the top it was incredibly windy! We were very glad we brought jackets with us! At a higher elevation and no wind block, the wind flowed freely and we definitely felt it. The noise was loud enough that we had to yell at each other to be heard. But still VERY COOL!!!
If you're in Ireland and in this area and up for a nice hike, (80 minutes up, about 40 minutes down) this is a good one!