If they were married any distance away from the area where the two known children were born it means searching dozens of parishes instead of just a couple, which makes the search much more difficult. The place to start the search for the marriage is definitely the parish that you know they lived i.e. Laragh/Glendalough at when the children were born, and if the marriage cannot be found there then start on the other parishes surrounding the area. Probably starting with Rathdrum to the south which is the next nearest location for a Carton household at the time of Griffiths.
Shane