Things are constantly changing, so I can't speak with exactness in regards to the upcoming schedule, but the way it should work, or at least the outline of it is you will start with what I believe is a 12 weeks course where you will go over all the basic sciences. You will cover biochem, immunology, histology, pharmacology, etc. After that then you will break down into specific systems that range from 4 to 8 week blocks. Cardiology, respiratory, renal, etc. And that is what you cycle through for the rest of the first 2 years. These are what we call the "systems" courses. All the while you will still have OPP, Clinical skills, and Community Doctoring. These classes involve OPP lab and lecture, simulated patient encounters, minority health, epidemiology, etc. So the "systems" kick in after you finish the introductory basic science class and last for the entirety of the 2 years, while all the other classes basically start when school starts and last for the duration of the pre-clinical curriculum.
Does that help at all?
The summer after 1st year is basically open. Most people I know took vacations, worked, went home, etc. Some did research, some did other random crap, but most people just hung out. There are no required activities during the summer so you are basically free to do whatever you want.