Hey OP. I'm not wise enough to pretend to know what's right for you, and I think this is a decision that only you can make for yourself.
For one, the comment about the difficulty of finding patients is something I have never heard before and something I do not think is true at all. I have many family and friends who see a DO in our area as their PCP, and most of them didn't even know he was a DO (or care). And I live in South Florida, which certainly has plenty of other options for healthcare.
If it helps, I was accepted to PCOM-GA and turned them down for another acceptance further away from home because I found some things about the program sketchy. Like you mention, the board study time situation is a definite negative. The situation with their clinical rotations made me uneasy, too.
However, there was a second year ambassador with my interview group who actually said he turned down Mercer to go to GA-PCOM. He didn't mention anything about a scholarship, but maybe that's what motivated him, because I remember thinking "why????". However, he said he wanted to be an orthopedic surgeon, so I definitely think he made a mistake.
My point is, no one can answer this for you: only you know yourself, what you're willing to sacrifice, etc. While it's true that you may find other passions besides PC while in med school, you mention that you would have to seriously love something in order to take on the extra years of training. How realistic do you think that happening is? You need to just sit down and look at those factors, as well as how debt averse you are. This is a really personal decision. I personally am very debt averse, but am not set on FM/IM so I would probably take the MD acceptance, as hard as turning down that kind of money would be. But, I'm also going to be basically the youngest person in any med school class, so there's that. No one knows your situation, and your mindset, but you. This is a tough decision, but hopefully you can make it as objective and realistic to your needs as possible. Good luck! Either way, you're going to be a doctor.