In your research, did you see that Mount Holyoke is a member of the Five College Consortium, with Smith, Hampshire, Amherst, and University of Massachusetts at Amherst (state flagship), which I think a pretty big advantage. Students can take some classes at the other schools and can otherwise share resources/opportunities. Info on this link:
Mount Holyoke has a beautiful campus and has terrific academics. And, yes Earlham and Mount Holyoke would be different experiences from Purdue, which is a large (and outstanding) public engineering/science/ag university, not better or worse, just different. Basketball and football would be huge there. Classes would be larger . . . and so would the amount of research being conducted, especially in science and engineering.
Good luck and enjoy the experience!