Interview days were similar everywhere, with some variations in length and number of interviews.
Arrive sometimes between 8-10 am. At a couple of places I was picked up at the hotel by someone, others I took a shuttle, others I drove. The most common thing was to take a shuttle or drive and then meet the secretary in the lobby. Secretary (or occasionally the PD) will give you your schedule by email or mail often ahead of time so you can see who you are interviewing with. It is nice to know something about them (their expertise, research, etc, because if you have similar interests that can be an interesting talk).
Then there are usually a bunch of interviews (range from 20 min to 45 minutes usually). I had a couple of interviews scheduled for one hour that did last that long, so be prepared. Most interviews are about 30 minutes.
At some places each person you interview with will personally take you to your next location. At others they will have someone take you from place to place so you don't get lost.
Most interviews are with faculty. You usually meet with people from different areas (a few CP people, a few AP people) unless you are straight CP or AP. Some programs have an interview with a chief resident. I met with the chair of the department at probably 80% of the sites, maybe even more.
Plan on anywhere from 5 to 8 interviews at each place. Most are low stress, some "tell me about yourself and your goals" type questions followed by your interests in pathology and the inevitable "what questions do you have for me?" At a couple of interviews they showed me a slide if they were doing that at the time.
Lunch happens at the appropriate time, sometimes with 1-2 residents, sometimes with more than that. No lunches anywhere I visited with attendings, although at one place there was a breakfast with an attending. There is always a tour, generally the tour takes place either before or after lunch. Generally conducted by a resident. Lunch is often outside the hospital, but some places with nice cafeterias will take you there.
Generally the last thing you do on an interview day is meet with the program director (sometimes for the second time, as a "wrap up" type thing. The PD will then ask if you have other questions, and give you information on what to expect. They tell you how they rank people, whether to expect to hear more from them (some places just don't really communicate). Often they will tell you their initial impression of you as a candidate (everyone liked you, we think you are a strong candidate, you're a butthole, you smell bad, whatever). Some places told me flat out I was a top candidate and would be ranked highly.
Following interview day there are varying degrees of communication. Some places call you, email you, write you, or do nothing.
Other questions? Things I missed?