And also, searching the top speed of a B-2 at 628mph, if detected at 150 miles out only gives them 14 minutes. Which is both a lot, or a little. Depending on how prepared for action someone is.
Well since there are so few B2 and they are essentially irreplaceable, I imagine standard wartime doctrine for the adversary would be to ignore target protection as a concern and go straight for the plane even at the risk of losing several of yours by flying over territory you don't control.
In reality, what would make a difference is coordinating communications and decision making.