I've found extraordinary luck when I've stumbled across bears while traveling. My method is to retreat to the point that I can go to the strategic map, then to go back to the tactical map, build a large deadfall and bait it. Six times I've done this, and with different characters, and EVERY time I came back the next day to find the bear trapped.
I think it works so well because the trap is well within the bear's range. I carry uncooked meat/fish and always have at least one cord on hand so I can build a trap when opportunity knocks.