In case Jim doesn't look in for a while: Matties is from 4pm Saturdays, the Skerries claims to be Wednesday and Saturday nights, but Saturdays are much the safer bet. Try to arrive at Newtown Cromelin in daylight, as it's quite a scenic route down from the north coast. Johnny Joe's is Fridays I think. Also a scenic drive, this time round the coast (taking in Tor Head if you've got time).

Depending how you're travelling, Belfast may easier to get to than some of these, in which case check Sessions (Northern Ireland) here (but note that the Kitchen Bar is now closed). The link also gives some Ballycastle sessions, which may be handy for you, depending where you're staying/working.