It is a ruin that is not open to the public.  Locals began an organization to secure ownership and preserve the structure, but that was back in 2000 - 2002.  To the best of MY knowledge, nothing much as been done.  http://www.kilmurry.ie/villages/carrigadrohid/carrigadrohid_castle/carrigadrohid_castle_survey_4.htm

Some 'close in' sites to tempt you:

It's virtually in MY 'Back Yard', of Millstreet!          http://www.millstreet.ie/blog/

Knocknakilla  http://www.megalithic.co.uk/article.php?sid=1043     http://www.megalithia.com/sites/w294842.html

Drishane Castle   http://www.britainirelandcastles.com/Ireland/County-Cork/Drishane-Castle.html

K

For Macroom:           http://www.macroom.ie/tourism/maps

Also nearby:    Carrigaphooca Castle and Stone Circle      http://www.irelandtravelkit.com/fourteenth-century-carrigaphooca-castle-and-stone-circle-macroom-county-cork/

                      Kilcrea Abbey    http://www.irelandtravelkit.com/majestic-kilcrea-abbey-ovens-co-cork/

                      Kilcrea Castle    http://www.britainirelandcastles.com/Ireland/County-Cork/Kilcrea-Castle.html

                      Carrigastyra Famine Graveyard      Background: http://angortamor.blogspot.com/2010/05/blog-post.html

How about Kilcrea, Beal na M'Blath, Kinneagh Round Tower (one of only two remaining Towers in Cork -- and has a UNIQUE base!), Timoleague, Kinsale and then home, to Ivy Bridge?

You pass through Coppeen on the way and Enniskean, after.

http://www.michaelcollinscentre.com/mick-collins-triangle.html

http://www.coppeenheritage.com/local-heritage/kinneigh-round-tower    http://roundtowers.org/kinneigh/index.htm  

http://www.coppeenheritage.com/local-heritage/cahirvagliair-ring-fort    

http://www.timoleague.ie/timoleague_abbey.html

Google Maps says 120 miles and 3.5 hours. 

Potential detours:

Rosscarbery :   Coppinger's Court  http://www.abandonedireland.com/cc.html

Clonakilty     :   DeBarra's  http://www.debarra.ie/       (Should get Keith's vote!)

Coppinger's Court.. a little less overgrown than it was in 2006 when we were there..it can be a hunt depending on the roadside vegetation... and there are cows in the field to be dealt with but they don't usually pay any mind to two-legged wanderers ...

That being said, it is a wonderful ruin

Bob's link wouldn't open for me...

so here is another... here