I am familiar with Pitt and agree that it is great for biology and would be a safety with her stats. The campus is relatively compact and is right in the city so there are sidewalks and crosswalks everywhere.
The big concern I see are the hills. The campus is built against a hillside referred to as “cardiac hill” based on how difficult it is for an able bodied person to climb. Many classroom buildings are on the main campus level but there are science buildings as you start going up the hill. Upper campus includes some dorms, the main rec center including the pool, and the main student parking lot. There are buses that drive around the campus to make getting around easier and I know there are students in wheelchairs that make it work for them, but if she is seriously considering a Pitt she should look into this further.