I'm not from the area so I'm not sure how observing works in your area.
When I found inpatient observation hours though, I emailed the head of the volunteer department of a hospital who directed me to the physical therapy director. For my inpatient rehabilitation center though, it was a smaller place and my family was looking for a place for my grandfather to stay, so I just asked to speak with the rehab director while I was already there and they said I could come in whenever!
So if emailing and calling doesn't work, you can always stop by and talk to someone in person. If that doesn't work and you have observed with other physical therapists already, ask them if they have any PT friends that would let you observe.
