Derry is nearer to Carrick than it is to Galway! I haven't spent hallowe'en weekend in Carrick for years but I remember it as a very informal affair of pub sessions. Carrick is a small place, west of Donegal Town, east of Gleann Cholm Cille. You can get the bus from Galway via Donegal Town and Killybegs. If you go there, don't miss Sliabh Liag cliffs.