I've had similar bugs before where it was like an invisible force field was surrounding an area, and if I crossed the field the game crashes. I have no idea what causes the problem, but normally I can set my video setting to really low, cross the problem area, and then everything works normally.
This time it isn't working. I even tried waiting somewhere for several days for the area to reset and I still crash when I try to enter the area near Fort Irony.
Has anyone else had this type of problem? Did you find a workaround?
Thanks,
-cwineman