I don't know exactly what your particular clinical research coordinator position entails, but it might be beneficial to get some experience where the primary goal is helping patients rather than gathering data or directing a study. Of course being a research coordinator is a valuable experience, but you should also have experience that involves helping patients. Again, I don't know the exact details of your position, so this may not be an issue.
512 equates to a 31, which is unfortunately below the 10th percentile for many top schools. The ones where 31 is the 10th percentile are Harvard, Duke, Cornell, Emory, UCSF, and Pitt, so those are the only ones that I can recommend applying to.
I see you are also planning on applying to UMass, Tufts, and BU. UMass is likely your best singular bet assuming you are an MA resident. BU has a median MCAT of 35 (516 equivalent), so I would classify it as a reach. Tufts is more in your stat range and is a good choice.
Other schools that you might want to look into in the NE are Quinnipiac, Jefferson, Drexel, Temple, NYMC, Albany, all the SUNYs (even Stony Brook even though their MCAT is a bit higher), Vermont, and Hofstra. Outside of the NE, look into schools like VCU, EVMS, Rush, Oakland, Wake Forest, and Virginia Tech.
However, this is highly dependent on your MCAT score. I would recommend making another of these once you have your scores back for real.