Reed, Carleton, Hamilton and Swarthmore appear highly in a Princeton Review survey, “Students Study the Most,” and, based on your *academic[/i[ criteria, may be appropriate colleges to research further:
https://www.princetonreview.com/college-rankings?rankings=students-study-most
I’d suggest you do not, however, interpret the list too literally. Hamilton, for example, would be influenced by their students’ participation in extensive sports programs.
I’d recommend Vassar as well.