Brendy, enjoy Castlerock i think its a fantastic course which is as tough as old boots of the back tees at a Par 73, i've played about a dozen times and look forward to it.
Haven't played RCD or Ardglass how close are they to Larne ? really fancy Ardglass i think its about £60 at the weekend i think.
Even better go to Donegal and play the 2 courses at Ballyliffin , Rosapenna and Dunfanaghy,as well as Rosses Point at Sligo and Murghvay at Donegal and Portsalon, great tracks.
Hour and a quarter if you get a clear run (faster if you wish but not advisable as the roads will have cameras). Ardglass for the general environment in which it sits is worth the money alone.
Played Castlerock on the way to Ballyliffin, hated every minute of it too because the weather was poor, had yanks in front wandering left and right, did 8 holes in well over 2 hours so gave up, only cost us £15 each as our clubs have an agreement in place. Looking forward to tomorrow as the weather is better and ther eis a load of us out and wont be so slow knowing the guys going.