Is there a recommended Level for Companions Quest?

I am playing a straight warrior at level 9 at expert difficultly and getting owned to the point of frustration in Dustman's Cairn. I have checked out some walk-through's on youtube and there are guys one shotting the baddies at level 6. Either they have the difficultly set way down or I don't know how to be a warrior!

Spoilers contained in my answer.

I went through the Companions quest line at level 20 or so, on Adept difficulty, and didn't really have a big problem with enemies (except the situation I may have related before when I tried to take the boss room of a Silver Hand hideout as a werewolf, forgetting that they all had silver weapons, which with werewolves is a baaaaaaaaaad combination).

The quest line itself is not horribly difficult to begin with on default difficulty. But I would suggest that you level up to 10 or above if you're doing a high-difficulty run.

I started the companions at about level 6, the silver hands and jobs they give you are pretty easy, although you do occasionally get a really powerful boss that you may need to wait a few levels to fight.