I read a bunch on this online. Nothing we did not do, but the below is what we plan, but never accomplish, for some reason.
When you are ready enter the gate and you will be met by Rigul the Uruk commanding these forces. He is a level 23 elite and will attack you aided by several of his lesser Orc minions. Destroy the Orcs and focus your attacks on Rigul. After you have worn him down a bit he will summon another group of Orc allies. Kill the lesser Orcs first. Trust me on this. Once the Orcs are down, refocus your attacks on Rigul. When he is near death Rigul will flee from the fight and release a level 23 Elite Mountain troll. This is why we kill the lesser Orcs first. Be mindful of the Troll as he has a nasty knock back and can send you flying. This is a long fight so use your resources wisely, keep your tank alive, and don’t bounce agro and you should come out just fine. Once you have defeated these last two creatures, speak with Candaith to complete the instance.
We did this quest with our main group.