Two New Yorkers on the ticket would create a problem for the Electoral College. I think Trump will convince Jim Webb, the former Democratic senator from Virginia, to change parties, endorse him and then bring him on the ticket.
Jim Webb would be a good pick. However, don’t know much about him. I think Trump’s achilles is with suburban/working women. I don’t know how much he would help with that demographic.
I can’t say anything about Electoral College issues, but it would be IMHO the closest thing to an unbeatable ticket ever. To assuage grass roots Conservatives and get them to the polls, they could name their Cabinet and Supreme Court nominees up front, loaded with fire-breathing, credentialed Libertarian types. Trump could announce Janice Rogers Brown as his first SCOTUS appointment. I’d walk over a bed of hot coals for a chance to get Brown on the High Court. So would many others.