Connemara or vicinity of Killarney National Park for hiking/walking base

I stayed in Clifden for 5 days and the bus connections are easy (and scenic)to Conemara national park. Kylemore Abbey which is worth a visit is also not too far by bus.
I went to the Aran islands from Doolin where ferry connections are so it's easy to go to the islands . Also Doolin has the Cliffs of Mohr,walkable from town, it was my daily morning walk.
Both towns are beautiful with a lively pubs playing traditional music. Friendly people but that's always been my experience in Ireland .

Either location would answer for your purposes, but Connemarra would be a lot less crowded than Kerry during the summer months.
We like Clifden too - it's a quaint little market town and the beautiful Sky Road begins just west of the town. It's one of Ireland's great scenic drives, featuring dramatic seascapes around every turn. It's also central for the very pretty Connemarra Loop drive that goes by the National Park (lots of pretty hikes in your range), Kylemore Abbey and the village of Cong - the "Hawk Walk" there at Ashford Castle gets rave reviews from many here on the forum. Potential side trips a bit further afield are the short ferry ride over to the isle of Inishbofin from the village of Cleggan - it's really one of Ireland's better kept secrets. There are boat tours out on the country's only Fjord from Killary Harbor just to the north, and if you're interested in a bit of Irish history the Doolough Memorial near Delphi is worth a stop - it's one of the most evocative places we've ever visited in Ireland. Can google it to see if it might be of interest.
Kerry is a possibility too, though I'd try to avoid the tourist crush in Killarney town at all costs - traffic congestion in the morning when the tour buses start to roll make getting on the road a real pain. Better (I think) to find a place midway between Glenbeigh and Castlemaine to be central for exploratory drives (and hikes) up to Dingle or over to Killarney NP as a day trip. There's also the very pretty Skelling Ring Road that starts at the village of Portmagee - lots of pretty seascapes there with spectacular views of the Skelligs. You can also book a boat trip out to the islands from the visitor center in Portmagee. The Gap Of Dunloe is one of our favorite day trips in Ireland. Can either hike (walk actually) the 7 miles to the head of the glen and back or book a pony trap with a local character for a bit of local color.
You really can't go wrong either way, but my vote would be for Connemarra.

Sounds like we should go with Connemara! Robert, would you recommend a day on Inishbofin over Inishmore? I've wanted to visit Inishmore for years but looks like Inishbofin is much closer if we're basing near Clifden/Connemara National Park.

That's a tough call Katie. We really enjoyed Inishbofin but then we'd already been to Inishmore, which has the Dun Aengus fort (worth a visit), and of course there you can hire bikes, book a pony trap, or hire a small van for a stress-free tour of the island ... none of which you can do on Inishbofin where it's leg power only. The walk around the island is quite pretty, however, passing by pretty beaches, a peat bog where we stopped to chat with a couple of local blokes harvesting the stuff, some old "lazy beds" - the layout of some ancient potato fields, and a picturesque old church not far from the village where the ferry docks.
For a first time visitor I'd probably suggest Inishmore, but I'd also recommend flying over versus the ferry ride which can be uncomfortable whenever sea-states are running high.