What are your goals? Do you plan on being in the military for a 20+ year career? Do you plan on getting out immediately after the HPSP/HSCP commitment if you are accepted? These are questions that would guide my answer.
If you plan on staying in career, consider USUHS - full pay&allowances (save pay for base pay if you are above O1, O1 BAH, BAS), $0 tuition - 7 yr commitment (not including time in residency, see other threads for more details).
If you don't plan on going full career (and I think this is what addresses your question), talk with a recruiter. I asked my recruiter's office about going directly to med school on HPSP right after PharmD school with HSCP - was told that it would have been fine, granted I received acceptance to the medical school. Obviously you could still go career with one of these, but in my eyes USUHS is the best option for a military doc who plans on going career.