I haven't tried this since the December update, but I did discover on leaving the dam main entrance, the Old Bear often spawned in the compound. If he didn't, going back into the dam then coming out again meant that eventually he did. This was useful as I discovered if you evade or scare him, then run out of the compound and shut the gate on him he never manages to leave it. I thought he'd just teleport out and follow me again as soon as I was far away enough but indeed he does not and I've done this a few times now, one time walking all the way to the cabin, then walking back to see him still stuck in the compound. Considering you have wolves to deal with as well on this final stretch, this makes the last part of the challenge a lot easier.