All jocularity about Sarah Palin aside, Trump really needs to pick a running mate who: (a) improves his relationship with the GOP establishment; (b) has executive experience on the state and federal levels, so he can actually run the government on a day-to-day basis while the Trumpster is off making his amazing deals; and (c) understands the workings of Congress. In other words, he needs someone like Dick Cheney, although preferably without the evil, which he can provide himself.
Chris Christie’s name has been mentioned, but he doesn’t really meet all of these criteria. In light of the upcoming showdown in Indiana, I would suggest Mike Pence as a plausible candidate.