Prior enlisted Air National Guard USUHS MS1 here.  There's a lot of  filler, but also a lot of valuable info in the 
USUHS  2009-2010 thread, so check it out if you have the time.  Also,  there's 
THIS  and 
THIS to  provide "inspiration" in writing your secondaries.  Also, Also, listen  to silverhorse84; she knows everything and tracked our thread as well  (thanks again!).
@ PmDawn (post #16):  I highly recommend typing it in whatever way you  can.
@ DavisStudent (post #35):  You won't go through MEPS.  You'll get your  physical through a contracted arrangement with whatever provider the DoD  chooses near you.  You'll go in with paperwork, they'll check you out,  fill them out, then they send them back to USUHS, then you wait.  I  couldn't pass the hearing test, then had to go through the hassle of  obtaining a waiver through the DoD Medical Evaluation and Review Board's  process, not MEPS, not quick and easy, certainly not same-day.  The  waiver issue delayed my unconditional acceptance by months.  BUT, it did  go through and here I am!
@ Ditto1114 (post #59):  Regarding HPSP, I remember one of last year's  applicants having some trouble getting into USUHS resulting from having  already made some arrangements with an HPSP recruiter.  Theoretically,  you should be able to get into an HPSP program, then bail for USUHS if  you get accepted there, but recruiters are super-territorial and if I  remember right USUHS couldn't/wouldn't "steal" that recruit from HPSP.   Not sure, personally, what the ground rules are with this issue, but  proceed with caution if you're considering HPSP.
@ skimsu (post #64):  I'm not on any admissions committee, but I think  they're looking for a solid understanding of military core values, an  understanding that we are a mission-oriented organization, why you chose  USUHS, why you want to join the military, your reasons for wanting to  serve service members and their families (as opposed to the general  public), etc.. etc...  basically a demonstration of understanding about  what you're getting into and an explanation of why you're applying.   Check out 
THIS  DOCUMENTARY if you need insight for the secondary or interviews.
@ burnettj (post #69 & 70):  We have 3-4 PHS students in our class,  and none of them look more than 1/8 Native American to me.  I haven't  asked them, but yeah...  The MD/PhD program is an interesting  military/civilian hybrid program.  The top line is that it's an amazing  place to do your MD/PhD and great for anyone who has the time and  resources to do it.  The bottom line is that you will spend 3 years  living on a $25K stipend in the DC area while your classmates are making  $50K-$70K (depending on prior service and/or dependents), and they will  move on to residencies while you're defending your dissertation.  That  said, if you think it's for you, then call the 
Graduate Education Office  before your interview to set up additional interviews with Dr. Metcalf,  some MD/PhD students, and various research faculty members.
@Bouddha (post #81):  Being prior enlisted is, I think, a giant gold  star on your application.  My class is ~ 1/3 prior.  I had a 3.8 cGPA  and a 27N with research experience and good references.  I can't give  you odds, but definitely apply and use that insight being prior enlisted  gives you as leverage in your essays and interviews.
@ Armywife06 (post #92):  Get a student host if you can!  My wife and I  have a small 1 BR so can't host, but everyone here is very helpful and  welcoming.  Having a guide to help you get around will be very, very  helpful.  Alternatively, there is a 
navy lodge very  close to campus you might be able to stay at.  Other hotels I'd  recommend are the 
Doubletree  on Wisconsin in Bethesda, or the 
American  Inn of Bethesda -- both are very close to base.   
The Hyatt  also looks nice, is in downtown Bethesda, and is right on the Metro so  you could easily tour DC before/after your interviews.
@ Coug (post #23 & 106):  Our interview day really was relatively  laid back.  I recommend coming a day or more early to see the sights -  and have more to talk about in the interview if they ask if you like the  area!
Re: emails  -  You're right.  This place lives on email.  We must get  10-20 mass emails about random things (like signing up to host an  interviewee!) every day.
@ robokittie1015 (post #111):  That was sweet.  
🙂   👍
@ Cyguy (post #123):  Usually 3-4 weeks.  First is the notice of  "conditional acceptance", then the paperwork & physicals, then  (hopefully) an "unconditional acceptance", then... GET READY FOR  TRAINING!  
😀
@ ALL:  Feel free to PM if you have any questions.  I still have some  links and contacts pertinent to the medical waiver process somewhere, in  case someone ends up needing that.  
General advice:  Unless you're re-taking MCAT, you can't change  your stats, so stop worrying about them.  Write (and re-write) your  essays, have others critique them, practice interviews, read a novel or  two (many interviewers ask what you're reading), and 
most importantly:   complete your applications as quickly and thoroughly as you can, then follow up on all the bureaucratic processes that must occur before you finally get your acceptance and orders to training (it's easy to get frustrated)!   You're on the home stretch, so don't start getting sloppy now.  
👍
Congrats to all who are receiving interview invites!  Remember to  relax and have fun, but by all means, even if you are a civilian, 
MAINTAIN  YOUR MILITARY BEARING.  
Extraordinarily long post, I know... I'm avoiding  studying for biochem.  😱