There are indeed buses from Cork to Dublin, check this site. You could also take a train. A bit more expensive, but also more comfortable (and with a toilet!).

I will check whether we can arrange a tour of Beamish (appointment only, so will have to call them). Other possible daytours are Blarney (castle and stone) and Midleton (Jameson Distillery). Not everyone has transport though, so I think we can leave it to the individual to decide what they want to do. There is a regular bus service to both Blarney and Midleton.

Another regular feature of Eurogathering are city tours, and I will check out whether these are available from the information centre. Who would be interested in such a tour? If Groningen is anything to go by, we need about 10 people to keep that affordable, so enter your name if interested.