I know how you feel. I will be 200K+ in debt when I graduate. This is the main reason so many people are driven to pick a specialty that is well compensated (e.g., Radiology, Orthopedic surgery) instead of picking the specialty they really want. The average family practice physician makes about 160K and a radiologist about 360K. That 360K is very alluring when you are inundated with debt. That's the unfortunate reality of medical education today.
As for debt reduction options, you already mentioned the two primary ones, HPSP and serving under served communities. Other than that, unless you qualify for some type of hardship grants, scholarships, loans, or whatever, you will just have to bite the bullet with the debt. If you are considering HPSP, make sure you go here: http://forums.studentdoctor.net/forumdisplay.php?f=72 so you know what you're getting into.
I'm not sure about debt management, since I'm not that far along yet. Your residency will probably be the toughest period financially since you'll be making 40-50K. It's hard making only $12/hour especially if you have a family and trying to pay off student loans, but once your training is complete things will be much better. The FAP is available during residency, but that also requires service in the military like the HPSP.
Study hard, kick ass on the boards, and do work on your clinical rotations and you'll be fine. Good luck, don't lose hope :).