Arrange an "accident" for Palin. It doesn't have to be fatal, just bad enough to provide a good excuse to replace her. Sending her moose hunting with Cheney is probably too obvious, plus I'm not at all convinced Cheney could take her. This will remove Palin as a liability, gain a certain number of sympathy votes, and allow him to pick a running mate without leaving much time for the press to dig up dirt on his new choice.
Have Bush declare a state of emergency and postpone the election. Then fight to get the election date restored. With luck he could both avoid the debates and play on his greatest strength: his record as a genuine war hero. I might be hard to pull off, but pretty much in keeping with his recent desperate plays.
Keep doing what he's been doing thus lulling Obama supporters into a false sense of security resulting in low voter turnouts. Meanwhile, count on the Republican base's utter lack of clue to carry him to victory.