Haha Scout.
Warrior21: Well it depends, what is your experience with working out? Was it during high school athletics or messing around in your garage weight room? What are your goals? Do you just want to be the three event stud or do you actually want to get in shape? I ask about experience because I don't want to recommend hang-cleans for someone who has never really worked out before. To be honest your preparation for AROTC will be mostly on the cardio side of working out as I have found that AROTC (and my limited active experience) muscular building/endurance training is well....lacking...
Generally people coming in have problems with pushups. Decline/incline box push ups 3x30 a few times a day is alright as supplement to a normal gym routine. Obviously bench press or dumbbell press will aid in getting those push up numbers up (pyramid sets ranging from 60-90% of your max 6-10 reps or more). Any big lift such as deadlift/squats/cleans will help leg endurance as well as build up your core for situps (Lower reps start at at 50-60% of max then build up). Band exercises and kettle balls can also greatly improve your oblique muscles.
Running: Interval training on the track has worked best for me. 2 days a week run 400m x4 800m x2 1200m x1 and mix the distances up. On the other 2 days run 2-3 miles (or whatever you can do at a even decent pace where you think you would pass the PT test). My my run time minimum to pass 16:36 so if I was a new runner I would shoot for 1600ish
I am not going to write a schedule up because I don't know what you can do. If you are asking for help on a forum I assume you are unfamiliar with working out so I recommend just doing push-up/sit-up pyramids before school or join a local gym and work with a PT. At your school the athletic dept should have workouts posted ( I have even seen ROTC ones made) which you should take a look at.