Where to base in Ireland for 4-5 days of hiking?

1. We've never been to Ireland and plan to be there in 2024 (but have been Europe many times to hike and we love the Keswick area);
2. We prefer to vacation in Europe in late April to mid-May;
3. We are meeting Swiss friends who are bringing their camper to Ireland to join us;
4. Where do you suggest we base so that our friends can have a campground to stay in and yet we can be close by in a B&B or hotel?
   
5. We would like to be in a place that offers at least 4-5 hikes; and
6. We will NOT have a car, but will be glad to travel by train to catch up with our friends. Traveling in their camper is NOT an option.

This does not mean we won't explore Ireland further, but we want to include some good hikes with our dear friends.
Thanks for your insight.