I’ve been to all four campuses and GW might be the nearest comparison. However, Pittsburgh is not as busy as DC and my impression is that Pitt campus is more spread out and greener than GW.
If she’s interested in the UK and PPE, how about Oxford? Your D’s ACT score would make her competitive, although as an American applicant the lack of AP scores might make it a bit challenging. The campus is stunning and, academic intensity notwithstanding (although PPE is reputed to be less intense), my impression is that it’s a magnificent place to spend 3-4 years.