Kenmare is a good base, you can do Beara and Iveragh from here.

Must sees:
Uragh (and Uragh West if you have time and dont mind a scramble)
Drombohilly
Ardgroom Outward
Dromroe
Derreenataggart West
Gurteen (a few minutes drive inland)
Kenmare for its odd situation

Then your about 20 mins drive from Kenmare to Derrynablahagh rock art and another 10 to Staigue rock art and fort.

There's plenty more worth seeing as well but if your short on time these are my personal favourite spots.