Do what we used to do when I was in an eod group and what the seals do mostly now. Crossfit. 30 min a day and that's it. Google it. There are also the caveman workout, any of the mma workouts but the crossfit site is easy to start with and if you can't do some of the lifts or don't have the equipment then they have substitute exercises. These are proven. The military guys that use these workout regaments hike with much more weight in much worse conditions than most any civilian. Just my thought.