The good news is that anywhere you go in Ireland will be rewarding. Also, as a west coaster, driving long distances is easy.
Killarney in May may be a miss for music, depending on the day of the week. Your other targets will all have great music, assuming by music you mean "session". We're a bit of a music bigots - we love a trad session but can take or leave your typical pub music - mostly drinking songs and top 10 covers.
I'm not a great fan of Killarney, as it can be very busy, and you can visit the National Park as a day stop on a route between other places. There are nearby towns like Clonakilty or Kenmare that are less touristy. They are also day-specific for music. Finding music is a matter of looking at Facebook or places like thesession.org.
I'd either discard Dingle or spend at least one night there. A day trip is a lot of driving for scenery that is visible everywhere.
We vary rarely spend three nights in one place, usually spending single nights, with the stops close enough together to get some time in each place. As I mentioned, most of the castles, ruins, walks, and Neolithics are not "in" a town, so the "base" travel method leads to a lot of backtracking or just missing things. The base method works fine if you're interested in "town stuff" like galleries, museums, shopping, etc. The base versus ramble travel methods are a hot debate topic on these forums, with our preferred method generally losing. We travel with just carry-ons, so uprooting on a daily basis is trivial. We use lodging to sleep and eat breakfast. As we get older, the idea of two-night stays is creeping into our plans a little, if the topology of interesting things dictate, although we're starting with a 3 week visit to populate.
My planning method consists of finding towns with likely music, then finding lodging within walking distance of the said bar, then using Google Maps to find "Things to Do" between towns. Shifting the overall vacation or reversing the order is then tested to see if the music odds increase. I'll admit to being OCD in the planning details.