I envy you your trip to this wonderful part of the world. There is a pub called the Irish Whip in Ballydehob that used to do a wide variety of music, ranging from rock bands to sessions to jazz and all points in between. For me though, the best place for live music and sessions is Schull, a little fishing/cheesemaking town on the way to the Mizen Head. About nine pubs, four or five of which will have music on any given night at that time of the year. Various tastes catered for, from 'tourist' to 'committed folkie'. Take your pick! Last time I was there I didn't have my instruments, but I was lent a guitar and mandolin for the week by a guy I met in a session. Also; try to get out to Crookhaven and Barley Cove (again out towards the Mizen Head). Crookhaven is a small harbour, from where Marconi sent the first signal across the Atlantic. For lunch try the Fish Chowder at Sullivans Bar, then see if you can talk Mrs Sullivan into giving you the recipe! (For an evening meal, try the Breton-run fish restaurant next door; even Mrs Sullivan thinks the chef there is awesome!)
Barley Cove is a beautiful, usually deserted beach, with tall cliffs and Atlantic rollers.
Have a great time
Tim