1) I'm considering applying to a massive number of MSTP/MD-PhD programs (10+; perhaps up to 20) in order to maximize my success rate. How grueling will this be to provide proper attention for during the Fall semester?
That's not massive--that's normal. Applying is not that hard. Once you take the MCAT, start working on essays. Interviewing is the tricky part. Try to take easy, flexible classes in your senior year. You can assume your GPA, MCAT, and number of interviews will get you in and let your GPA sink a little. Of course don't get any Ds/Fs, but programs don't really care about that year semester as long as you get accepted. A few Bs aren't going to significantly hurt your near 4.0 GPA anyway.
2) I'm assuming I'm within the mean of the applicant pool here, but in all reality, where do I stand?
You're fine. Need an MCAT score.
3) If all goes to hell, (two scenarios:I get a crappy MCAT score due to rushing it all or I don't make anywhere I've been invited to interview at), is it advisable to take a year off, research, study for the MCAT, and reapply?
Sure, that's fine.
4) What advice can you give on the personal statement and interview process?
Worry about it when you get there. Read old threads on SDN. Those aren't the hard parts of this process.
5) My main choices are currently SUNY (Stony Brook, mainly) schools, as I'm a NY resident, and I feel they would respect my home institution more so (CUNY). Does SUNY in general take a lot of NY residents into their programs? Can anyone tell me what doing an MD/PhD at Stony Brook is like?
State residency is not a factor in MSTP admissions. Many people choose to stay in their home states, so they tend to be a bit overrepresented in their local MD/PhD programs. But your undergrad institution isn't really an issue here. Apply as locally or as broadly as you like, but I do think 10-20 programs is a good number.
A lot of other advice got thrown around in this thread. Here are my takes on them.
-- If you need to lay off the research this summer because of physics II + MCAT, it isn't a big deal. It's unlikely anyone will notice or care.
-- I don't see why you need to take a year off. You can take Physics II this summer and prep for the MCAT. My general advice for MCAT prep time is as follows:
~1 month full-time studying
OR
~3 months part-time studying (~3 hours per day)
I always recommend a prep course for safety purposes.
-- You could take the MCAT as late as August if you wanted to. September would be possible but late enough that it could hurt you. Yes, early applications are good, but that is not a make or break factor here. MCAT score is the make or break factor. Thus, DO NOT UNDER ANY CIRCUMSTANCES rush into the MCAT if you are not well enough prepared (i.e. scoring 35+ on practice exams). That's when we look at going into year out territory.
-- You're going to start volunteering/shadowing now. Good. My general guideline is to get at least 50 hours. This really isn't all that hard to do.
I don't at all see why you
need to take a year off. You obviously seem opposed to the idea, and what you're proposing is perfectly feasible.