Looking for a winter exercise program
 

I am sure this forum contains all the answers I need, but maybe someone can help pointing out where:

What I'm looking for
I am able to mash the ball pretty well with everything up to the longer irons, but past that I feel I am not quick and strong enough to really lash it every time with the longer clubs.

So: I am "sort of" looking for a practice regime that will make me better suited for lashing it with less effort and more precision.

Currenly I feel I am more "heavy" than "quick" and that lack of core strength keeps me from performing as I'd like.

Thread links, anyone?