Aslivey-
I spent 10 years as a Naval Flight Officer, and worked closely with many Navy Docs. I'm also on an HPSP scholarship. Here's a couple of things:
Remember how the flow goes for "us:"
Rotating Internship (1 year)
GMO Tour (2-2 1/2 years)
Residency (3-4 years)
Payback (1 year for each year of Med school or residency, whichever is greater)
Usually, "payback" is only the time you have to do for your residency or med school. Past that, you usually don't do stuff year by year. More likely, they'll encourage you to stay in for 2 or more years by offering you bonuses and fellowship training. The obligation will be a certain number of years depending on how much bonus money you take.
Not sure if the internship year counts towards a primary care residency. Most likely, it will depend on the residency program itself, so you'll probably have to contact the residency director at the hospital in question.
Interns do not deploy. The GMO tour is your most "vulnerable" tour in terms of deployment, but it depends purely on the billet. Certain Naval Air Stations have Flight Surgeons, and these guys do NOT deploy. It's usually only the CAG (Carrier Air Group) and FMF (Fleet Marine Force) Flight Surgeons that go on the boat or out with the Marines.
Of course, the GMO tour isn't technically "required." The Navy likes them, though, because it fills a lot of much-needed billets in the operational force. With the recent unpleasantness, I would say that they are going to be very common (read as: required) of most graduating med students. (Just my opinion). Of course, most will agree that they are the most "fun" tours that you will do.
The second huge "plus" for a GMO tour is that it bumps you way up the list to match for a residency. If you really want to do a particular residency at a particular place, I'd say that you're best bet is to do the GMO tour. If you're fresh out of school, competing against all the other bubbas who *have* done GMO tours, plus the prior service guys, plus the people from USUHS, I don't think you have much of a chance.
The "detailing triangle" consists of 1.) The needs of the Navy, 2.) Your performance 3.) Your personal preference 4.) Special considerations (Yes, that's 4, which should give you an idea as how the bureau of Naval Personnel works).
Obviously, the long side of this rhombus is the needs of the Navy, but the other ones do have some influence. I negotiatied for 3 sets of orders in my career, and always got what I wanted. Some of my buddies did too, others got screwed. My experience has been that if you do have to take a "hard fill" job, they usually try to make up for it down the road.
The other time that you're "vulnerable" is after the residency. This is your true payback time, and they need Docs in Guam, Japan and Spain just as badly as they need them in Bethesda and Portsmouth. This isn't ship time, but it's not San Diego, either. (My roomate went to Guam as an Internal Medicine Guy...likes it, though.)
Of course, one of my favorite quotes from the bureau: "We didn't lie to you, the truth changed" is also true. You can never truly be sure you got the orders you wanted until you check in for them.
Look at it this way, though: The only really big Naval Hospitals are in San Diego, DC and Portsmouth, so at *worst* you have a 66% chance of getting the East coast for a residency!!!
(On a personal note, San Diego is a million times better than any East Coast location anyway)
Here's the www for the Naval School of Health Sciences, they might be able to take any specific questions for ya. (Just remember that thing about the truth changing!)
<a href="http://nshs.med.navy.mil/" target="_blank">http://nshs.med.navy.mil/</a>
Hope this helps.
Cheers,
-sb