Outcast's Path

Please provide more details about this point. Did you go to the Elves after receiving the quest to eliminate the Orcs? What do you mean by "they won't let you into the Castle"? You just need to go to the bridge in front of the Castle, not into the Castle itself.

Yes, exactly. I received a quest from the Chief Human to capture the Orcish Castles. A message appeared saying that I needed to go to the Elves. The passage to the bridge is blocked (where the Elf stands and gives quests).
An army of Ents was guarding the Cloak of Silana and something else similar (like a Ring of Warning). But these are not valuable artifacts; you can buy more serious ones in the Castle...

You can get the Stone of Ancestors by defeating the Elves, which is perfect for those playing as Orcs.

I didn't have that quest (probably because my reputation was too low).

I think getting 75 reputation with the Humans while playing as Orcs is quite achievable.

Most likely, that's the case. I currently have a reputation of 90, and I haven't completed the quests about the Grail, the Meadery, and I haven't delivered 10 barrels yet – that's another 12.