I'd say number 4. There are mature bucks everywhere. You just have to have access to hunting areas and then find them. Especially since you stated mature deer, not their score.
Is No# 1 for me......but not location as in country - but location as in your woods. When you set yourself up in the correct areas for mature deer......all the other stuff takes a far away back seat.......All of it
Why am I thinking that coincides with #4 also.