First of all I want to thank you in advance for your service to our country. To prepare for boot camp, start with flexibility training and find an exercise activity that you enjoy and wont be a chore but will engage you mentally as well as physically. (I recommend kickboxing, but if you see my hub site you'll understand the bias) To overcome boredom on runs, find a running buddy and pick interesting beautiful trails, that helped me. In a pinch, jump rope is a great alternative to running it improves your cardio and you can do it to music. You will be carrying alot of gear so fill a backpack up with heavy items and practice hefting it around on long hikes.
I hope this helps. Good luck.