In Rostrevor as Paul said, Red is an excellent (XC) loop pure class, BUT....! the Black loop has a 20-25min Enduro descent (big bike style) rides really well the climb for both is the same trail (a killer)
Also would recommend the uplift service for 'Mega Mission' its a real skills delevoloper (I did it seven times in a row so good..! and also an easy roll) now 'On the Pulse' is a downhill track (great fun even on Enduro bike but tricky Be Careful..!) Enjoy super trails good food (visa or sterling needed)