For a rigorous (but not necessarily up-to-date) answer, you might want to look for a couple of NSSE assessment reports for these schools (if they are available) or peers. Just to see what they looked at, if nothing else.
Here’s some old reporting on Kalamazoo:
https://cache.kzoo.edu/bitstream/handle/10920/26491/NSSE%202002%20Mean%20and%20Frequency%20Reports.pdf?sequence=2&isAllowed=y
Page 5 (“time usage”) indicates about how many hours per week students spent preparing for class and on other activities.
That was many years ago. Then or now, the numbers will vary by course, by major, by student, and by the week of the calendar. I’d expect most of these schools to keep most students rather busy with classes, “homework”, and co-curricular activities. I mean, there’s not much point paying the prices they charge if you’re not going to put in the effort.