Depends on the school. I
They all have to be approved rotation sites with credible patients and teachers. If the patient count is low or the doctor not very credible, tough luck. My understanding is that at some schools you can do an application to make your own rotation site but it can be a pain.
New rotation sites are added and changed all the time, so keep asking students and checking the lists. Most schools clump their rotation sites around the school, ie PCO has most of their sites in PA and the surrounding area, but all schools branch out a bit.