Out of the three, I dislike Kasich. I actually liked a lot about Rubio except I don’t trust him on immigration. I like Walker too but he wasn’t ready for primetime. Kasich is a liberal and Hillary will probably woo him for her VP pick.
If he could convince Susan Martinez, or Nikki Haley, that would be good. Sure, it's pandering, but winning is paramount, and they'd help him with his biggest demographic weakness.