Its very hard for me to make a pick, I would take a tag for a Mule Deer or Elk in ANY of the rocky mountain states, they each give you an opportunity at a big animal.
But if I really had to pick one, I would pick an Arizona Mule Deer tag. I would go un-guided and give it hell trying to find a book animal. I think I could do it, but only because Arizona gives you an absurd 365 days to fill your governor tag if I am not mistaken!?