I had to run this one last night. Corso's affection needs to be in the 5000 range and I was on Hoth (level 39) when he spawned the conversation.
As another poster mentioned, the cave entrance with the alternate path was red for me. I ended up circling Camp Arnek (I believe that's what it's called) to the south until I found a portion of the wall that I could stair step jump down, then circled the parimeter of the camp and ran past the level 50s guarding the back entrance. Once I recalled Corso from his single minded need to distract said level 50s, all was good and no deaths. lol
Oh, and as someone else said, the mission really wasn't worth it, Corso didn't even say thank you afterwards. But, at least now it isn't permanently stuck in my log.