bearhuntr,
In my opinion, put a a good scope on your gun. I would not be concerned with a distance as the issue for the scope as much as I would be concerned about the need for light to see your iron sights.
You likly will be hunting in woods with a heavy canopy. Late in the day, when most bear are taken over bait, having a scope could mean the differance between taking the shot or not. In low light, trying to find your iron sights is a real challenge.
I had three occasions to shoot bear over bait in Maine. All 3 times, without a scope I could never of shot because of how late it was and how low or near dark it was.
A good scope could close the margin. It will at minimum, give you the most amount of shooting time.
Something to consider when trying to decide on a scope or not.
Cabin4