I shadowed the asst. PD for IM at a local hospital and it was great in that it was in an academic environment. I was able to talk to med students, pharmacy students, attending pharmacists, residents, and attendings while attending rounds everyday for the whole summer. Let me tell it was quite the group. I learned sooo much. Asking questions, being questioned. In the afternoons I did research and or shadow a DO at a semi-urban clinic or shadow a DO at his private practice. Sometimes attend lectures, morning report, pharm. lunches, etc. Some will just stand by and let you observe. Some ask you questions. Some ask you if you have any questions. It varies. Because it was in a hospital I was able to scrub in and view a surgery, spend a few overnighters in the ER, and see an autopsy. The best part about it was I realize now I do not think I want to do IM, Pathology, or Surgery but would enjoy ER.
Try to search for hospitals that have some academics and find a D.O. within to shadow. Chances are he/she know many people who you can shadow to get a taste of as much as possible.
Good luck
Raptor5