In reply to Jim C:
There are a couple of books devoted to the mountain area around Carounthill and the 'Reeks. The ridges are superb and Howling ridge, which has been mentioned, a relatively simple scramble was only climbed as recently as the 1980.s
As for what else to do, it depends what you are interested in. Killarney was once described as "best seen through your rear view mirror" and is really a place designed to extract money from tourists.
I found the most interesting way to find out of the way wonders you'll not see in the UK is to buy one of the OSI maps at 1.50,000 and simply look for the antiquities - all marked in red. You'll discover the quite Ireland, off the beaten track, ancient medieval churches, squat and solid, often still used grave yards, ancient holy wells, often still used by one or two locals and enough stone circles to last you a life time. Some of them small enough to fit in your average front room! Lots of the old landlord houses were burned in the 1920,s and make interesting excursions. There are dozens and dozens of ancient Tower Houses (mini castles like Blarney Castle but without any visitors) dotted around the place. And you'll not see another tourist even in mid summer. Europes oldest copper mine is on Ross point near Killarney & the lakes, although this will only interest those in seeing a small cave in a rock face and lots of green rock.
The 'Must see' tourists traps, are in my place vastly over rated. Kate Kearney's cottage, (a cottage no less) Killorglin (Of puck fair fame and an excuse if you needed to get pissed and slip in the vomit on the streets), the Gap of Dunloe which the local trap drivers have commandeered for their own use) are best avoided.
An interesting read on 'tourist Ireland' try Vitali's Ireland by Vitali Vitaliev is an outsiders view and not dressed in tourist attracting verse.
Some of the flora and fauna in the area can only be found there and in some of the warmer Mediterranean areas, this includes The Strawberry Tree, The Kerry Slug and several unique plants, insects and so on.
I hate to say it, but the Ring of Kerry a sixty odd mile round trip is spectacular if, and I mean if, you can choose a weekday, setting off very early (before 10am) and on a reasonably day provides a spectacular coastal drive, unequaled by any in the UK.