When you say she wants to major in percussion at a liberal arts college - are you talking about pursuing a BA rather than a BM? Or just that you’re looking for a conservatory style program within a liberal arts setting?
When you say Bard - are you talking about the conservatory? It has a phenomenal percussion program - run by So Percussion. But it will be a difficult admit - musically. They only admit a couple of students per year. And she would be required to pursue a double degree with a BA from the college in another area. http://www.bard.edu/conservatory/undergraduate/percussion/ (And their Facebook page: https://www.facebook.com/bardpercussion/timeline) It looks like the Artist Teaching Fellow with So Percussion (currently from Mobius Percussion) teaches private lessons in the college, and there is lots of jazz and latin drumming. Depending on how seriously she wants to pursue percussion she would need to decide if the college pathway, rather than the conservatory, would satisfy her enough. If she is interested in a double degree, she should also look at Eastman/Rochester.
Oberlin has a very good percussion program - again, in the conservatory.
As for liberal arts schools in the Northeast which do not offer a BM - Vassar, Wesleyan (which will have fantastic world music percussion), Skidmore, and Williams are always mentioned as being strong musically.