‘I am looking for a top LAC with intellectual people who have deep discussions about science and art and stuff but who also drink/party a bit on occasion in relaxed settings, like in dorm rooms with a group of friends’. You can find this at any of the schools you listed. You need to search out this group, by meeting as many classmates as possible, joining relevant clubs, etc. I do think that it’s easier at some places than others, you seem to have a good read on Dartmouth, and maybe a less frat-oriented school would make better sense for you. Having said that, admission to any of these top schools is for from guaranteed no matter what your credentials, so you might keep Dartmouth on your list and see where you get in. Good luck - with your great attitude and desire for learning I think you will enjoy college no matter where you end up.