Thanks for the advice everyone! Not completely disheartening. I'll be sure to post my success or lack thereof if I succumb and pick it up on opening weekend. If I can get it running, I guess I can always try to toggle grass, and see if that helps. It seems to help with other Bethesda games. It would be a shame to toggle the hand-placed trees, but I wouldn't put it past me if it means being able to play.