Base for exploring Dingle, Ring of Kerry and points south

The Aran Islands are a bit of an outlier in this plan and there isn't really a sensible base for doing them along with ROK and Dingle peninsula... Boats leave from Doolin, Galway City or Rossaveel. You need to relocate north and spend possibly a day either side of the day trip in one of these areas.

ROK and Dingle can easily be done from one base - Dingle or Killarney are the obvious choices with plenty of accommodation and tourist facilities. If you want somewhere smaller and quieter, have a look at Killorglin between the two. (Doolin or Galway are to be 3+ hour drive from Killorglin, longer from either Killarney or Dingle....)

Despite Rick's advice, you may want to look at Killarney. It has transport options, good hotels and pubs for a small town, lots of good stuff to explore right in the immediate area, and is a good jumping off point for Ring of Kerry sites and as an easy day trip to Dingle. It would be a bit of a long haul to Doolin / Aran Islands, however. Again, some will tell you it is overrun with tourists, but we were there in March and it was lovely and uncrowded (and others on this forum have suggested that offseason or shoulder season makes it less crowded with still all the benefits of a busy summer tourist town).

I realize there's an almost evangelical split between the way people travel, but I've never understood the idea of using a "base". We find that simply moving between towns in a logical order is easier than the drive back to base at the end of a long day of mostly driving. We travel light and never actually unpack (never understood why they have dressers and armoires in rooms) and checking out and back in is far, far faster than the added driving of a return to base. Maybe if your traveling with a large group it makes a little sense. If you actually stay in Dingle, relocate to Doolin or somewhere like that, then relocate to Galway and maybe stay overnight in Kilronan, you do a lot less driving and see a lot more. Only the Rings (Kerry, Beara, Dingle, Sky Road et al) lend themselves to an efficient return to your base. The only good reason we see to stay longer in one spot is if we're staying in a very homey B&B with interesting hosts and lots to do within a very short distance, which is unusual, since the things we enjoy (hiking, ruins, birds, Neolithics) are usually out in the countryside so we see them while relocating. We always stay in small cities/towns because we want to be within walking distance of a good pub with good odds of having trad music and the requisite Guinness and/or whiskey (note the "e").

Thank you Wasleys and Steve. I'm plotting out an itinerary for towns I haven't seen and will add Killarney to my list.

I would suggested breaking your stay in to 3 'bases' to make your visit more enjoyable and enable you to see all that you want in the areas you missed last time. Dingle is a magical little town and if you are still planning your itinerary, I'd suggested staying there for a couple of nights. According to my Irish relatives, it is the most 'Irish' area of the Republic (the community preserve the traditional Irish culture and language.) If the Aran Islands are also on your list, I'd suggest staying in Doolin for a couple of nights. You can take the ferry from Doolin to the Aran Islands and you can also walk from town to the Cliffs of Moher. For ROK, we stayed in Kenmare (with a stop over in Cahersiveen--not recommended--but needed to for our tour of Skellig Michael.) Hope this is helpful!