I think Columbia ended up edging out Barnard in part because we had dinner with a friend who graduated from Columbia while we were there and he talked about how much the core meant to him—even 30 years later. We left dinner and my daughter said… what other time in my life will I be able to read Plato and talk about it with a bunch of other people? She hasn’t gravitated toward strong core programs elsewhere. 
We’ll check out Carleton, too! Thank you!
Oh! She actually prefers PPE over Political Science but so few places seem to over it. Will definitely check out Denison
With such great accomplishments, why pay full? I know that’s not your question - but there’s lots of top honors colleges to compete against the liberal arts schools. They’ll give so much in aid - you can take the difference and save for your daughter for a car, house down payment, whatever. Just saying. Most big schools have Honors and solid newspapers - but the top Honors are ASU and U of SC but so many public schools have great Honors. You could go for 30K a year. There are even public liberal arts schools - UNC Asheville, Florida New College and more.
All the LAC schools mentioned are great. Per Princeton Review, the best papers are at Bowdoin, Grinnell, Loyola New Orleans (you can cross register at Tulane next door), Scripps (one of the Claremont Colleges), and Eckerd. They do mention U of South Carolina -which many consider the top Honors College and your daughter would be a strong candidate.
Best College Newspaper | The Princeton Review
Another website adds Bucknell. And another says Oberlin.
Good luck.
Look into colleges with an available public policy major, which relies on the fields of political science, economics and philosophy for its foundation.
Another plus for Wesleyan is its College of Social Studies which has been in continuous operation since 1959, the great-grandfather of interdisciplinary social science programs (there’s also a sister program in the humanities, the College of Letters):
https://www.wesleyan.edu/css/
Also many colleges allow students to create their own major so that may be a possibility as well.
Princeton Review has a list of best college newspapers, based on surveys of students’ opinion The list includes:
Bowdoin
Grinnell
Scripps
Eckerd
I’ve seen the following mentioned elsewhere:
Bucknell
Brandeis
Tufts
You’re right that very few places offer PPE, but with that as an interest, I’d look closely at Conn College. Read closely how they approach the integration of undergraduate studies, especially through their concepts of Connections and Pathways and through their interdisciplinary centers. Even within departments like Economics, Philosophy, and Government (their name for Political Science), they think broadly and in an interdisciplinary way.
See what you think.
Williams College
The Williams Record is a great paper, with high journalistic standards and remarkably balanced reporting on a campus that is less balanced overall. A very admirable paper. Great group of kids, too.
Kenyon offers one of the finer core programs in the country. It’s less known than some others, probably because it’s not required, but this might result in its attracting some of Kenyon’s most intellectually engaged students.
https://www.kenyon.edu/academics/departments-and-majors/integrated-program-in-humane-studies/
As a safety school, check out Dickinson College. Student newspaper is very active and has a website, check out thedickinsonian.com ! Political science is a popular major at the school, which also has a strong pre-law program (check out their 3+3 partnership with Penn State Dickinson Law) and a big focus on community engagement, with many students having joined the Peace Corps.
Columbia is fantastic, but she can do that anywhere. To me the Core vs. open curriculum is about what you’ll do with the freedom. My D was a physics/astro double and took philosophy courses on rationality and epistemology, a fantastic course on biofeminism that stands out for her to this day, and several others. She can read Plato at Barnard too.
Of course she can read Plato anywhere. I think she was referring to the community that grows out of the Lit Hum experience at Columbia.
I think that you’ll find that community at any worthwhile LAC.