How to get in archery hunting shape...

I'm still new to archery hunting, but I am familiar with being in the mountains and what is required.  I have found as I have begun the process of getting into archery, there are several areas where I am lacking.  The first area I need to be focusing on is my core.  I have always been week in the stomach, back and chest.  This is an area I am still working on figuring out a good exercise regime, but in the research I have done, good old fashioned pushups, front crunches, and back crunches seem to be best.  I am giving it a go by starting with 25 pushups, 50 front crunches, and 50 back crunches a day.  I hope to be able to work up to doing 100 of each in a day.  In addition I have a target set up in my basement where I shoot daily.  The target is just in a storage room where I only have 5 yards to shoot, but this will at least build the strength necessary to be able to draw and hold steady so that I can shoot accurately.  Basically the goal with this is muscle memory.

The other area to focus on for me is getting mountain legs and lungs.  I am fairly in shape when it comes to running long distance on flat ground, but when it comes to stairs/steep mountains I run out of breath quickly.  In addition, when it comes to hunting season, I will be carrying a heavy backpack as well as my bow.  I discovered a quick way for me to simulate these scenarios in my regular morning workouts.  The target I use for shooting in my basement is a bag target from Scheels (similar to this).  Using a couple of bungee cords, I was able to strap this target to my backpacking backpack.  I then go to the hill that's about 1 mile from my house and hike up the hill carrying this backpack with the target attached.  In addition to helping me get in shape for mountainous terrain carrying a backpack, this also happens to be in an area where I can carry my bow and do some field shooting.  I hope this provides a better simulation for the shooting conditions when I am in an actual hunt, while also getting me in shape.  It doesn't seem like much I am sure, but after only a week or so of these workouts I am already starting to notice a difference in my level of tiredness during my workout.  As I continue to progress I'm sure my workouts will change, but for now I feel like I am making a good start.