Military MD's second item cannot be emphasized enough. Make sure the program director at the program of your choice knows who you are and wants you at his program. This is huge, and stay in touch, do not let him forget who you are.
Wherever you go to do a GMO tour, there should be a DOD hospital. Go to that department and volunteer some time to rotate, research, etc. Get to know the active duty people in your specialty, find out who they know and make use of the contacts. Scores, grades, etc are set at this point, but who you know can make a big difference, especially in a very competitive field like Radiology.
If you do a one year hardship tour, you must begin very early, and this can be difficult. You need to strike a balance between being essential and **** hot at your new command while rapidly finding time to go get face-time at the local hospital. A tough balance to strike. Since you said Korea, I assume you are Army, so I don' t have much advice specifically. All of the people I know in the Navy who did one year tours in Okinawa returned to the specialty of their choice, but all were very well qualified and had laid the ground work for their return before they even left. Good luck.
DD