Hey guys, I’m really grateful for all your comments, they have been immensely helpful to me.
I think I’ll take your advice and go for the drug free housing, my parents (and the organisation that’s paying for my education) will probably be a lot happier that way xD So I guess from what you guys have told me, there’s really nothing to worry about in terms of drugs, drinking, or diversity in both Vassar and Carleton.
As for the other things I’m considering now: Right now the major thing that Carleton has going for it is that the culture seems like something that I would enjoy slightly more than Vassar. However, I am aware that I don’t need (and it’s not possible) for the whole school to ‘fit in’ with a generalised culture that I like - I just need a couple of people that I like and will get along with, and I do believe that these people will exist in both schools. Likewise, I think in both Vassar and Carleton there will be people that I won’t fit in with and that’s completely fine. So I’m not sure how much this perceived culture advantage Carleton has over Vassar should hold sway over my decision.
On the other hand, Vassar has the weather going for it, the campus, and I guess to a small extent the state it’s in. Another thing that I don’t think I’ve mentioned before is that I would want to take up varsity squash (I played in high school for my school & country) and only Vassar has a varsity women’s squash team. I don’t think any of these are particularly big factors (especially since I’m totally fine with trying something new and not play squash, there are so many cool new clubs to join at Carleton and Vassar), but they’re definitely things that counteract Carleton’s ‘culture pull’ for me.
Also I’ve heard from some people that although Carleton has a higher ranking, Vassar is equally well-known (if not more so) because it’s very established with a rich history (seven sisters’ school or something) so I think this factor is tied as well.
I’m sorry if it seems like I’m still super unsure (I am) despite all your help and insights haha. I also wish I could’ve visited and made up my mind from first-hand experience 
Don’t worry, I will definitely post my eventual decision (gosh how I wish I were at that point now) here. I totally agree that I’ve gotten absolutely wonderful responses, and I’m incredibly grateful for that.