From one old fellow Marine to another--
I can tell you that a lot of the training that you're likely doing now can help you lose weight and bulk up, but at 5'7" and around 195 lbs. and a body fat percentage of less than 10, you're doing pretty well already. If you can train using weights, all well and good, but if not, you'll have to improvise.
For starters, how many pullups can you do, just body weight? When I was on active duty we had to do gazillions of 'em. Why? Because you had to have the kickass to climb those nets on the side of the ships, and the rail of the ship usually seemed as far away as the top of the Empire State Building at the time. When you get so you can do a bunch of them - I'm talking chin-ups as well as pullups (know the difference?), try adding some improvised weights, like, say, clutch plates that maybe you could scrounge from the motor pool. Try the same thing with pushups and dips. For a squat bar - how about a drive shaft, one that's due for replacement because of wear (I used to be in motor transport and at one time had a truck platoon, so use your imagination but don't commit any crimes, and if you have access to proper equipment, USE IT!)
When your squats and, say, bench presses start getting hefty and you can't work out with spotters because you're by yourself, always improvise safety bars or some device that will let you set the weight down without your having to drop it onto the floor.
I'd suggest plenty of good chow, go easy on the processed carbs if you can (i.e., did those mashed potatoes come out of a box or are they real?) - I know, I know, your choice of foods in the mess hall ain't exactly like a gourmet restaurant - and check out the various diet suggestions that you can find here on this Web site. Each of us is a little different from the next (thank goodness!), so that what seems to work perfectly for one guy may not work so well for you.
Do you have an allergy or even a low-level sensitivity to any foods? More people do than think they do, and sometimes the symptoms are not overwhelming in that you don't get, say, a rash or your lips don't swell up when you eat certain foods, but your pee and poop may become irregular or you get a certain bloated feeling - or you may not be able to shed those last few pounds of body fat that would get you from say 12% down to 6%.
Semper Fi, my friend - and go get that bastard UBL.
One last thing - if you have access to an Olympic bar (NB, they're slightly thinner by a couple of millimeters than a power bar) and some Olympic weights, get somebody to teach you how to do power cleans and snatches. Always use collars or hose clamps to keep the plates in place. Google Olympic weightlifting and you'll come up with some sites where there'll be videos of the different Olympic lifts, and lots of training tips. You'll soon learn that nothing feels better than a good snatch.
Don't neglect ab work. Most of us hate it but I can tell you that about sixty percent or so of your power comes from the mid-section of your body, and the guys and gals who train at the Olympic Training Center in Colorado do a lot of it. If you've seen any Olympic lifting lately you'll have seen that lots of the Olympic lifters aren't even wearing lifting belts. I do it three days a week, first thing I get up.
Once again, Semper Fi and Godspeed.