Relationships: Something you don't need to be worrying about right now or in dental school, if it happens it happens, and it is something that can happen anywhere; I'm sure there are attractive males at Case Western as well. Just not a good thing to factor in, unless it borders on marriage/children level.
Family/friends: Yes, this sucks, but this is another thing I'd put little emphasis on. The first year it will be hard, but you will also be neck deep in school, so while you may long for those comforts, you will also be so focused on academics that they will likely take your mind off of that longing a lot of the time. And after that year it'll get much much easier (Source: having lived 3k+ miles away from family/friends from 18-27). Also, flying 2000 miles is cake, unless you have some kind of fear of flying. You wouldn't expect to be hanging out and visiting friends/family all the time even if you were living near them, would you?
City: I don't know anything about the city for Box 1 (Cleveland Ohio, right?), but plenty of people go to much worse places (Detroit?) for school and do fine with it. So I wouldn't consider this too important.
Weather: Ugh. This one actually counts IMO, and it's a known fact that weather can have detrimental effects on different people psychology. This is actually one of my reasons for focusing on West coast schools (I lived in NYC for 5 years, after having grown up in Hawaii, it sucks and I never felt I truly got used to it). That said, you can overcome the weather thing too, we aren't talking the rest of your life, 4 years is doable.
Schools: Personally, the whole school thing means nothing to me, other than UoP which gives you a shorter time in school. Otherwise it's all the the same (I won't bother bringing up the whole "networking" thing, "research", etc, whatever). Though you sound like you have more personal respect for Case, or something along those lines.
Cost: So, when it comes down to it, 90k does actually matter. That's not some tiny sum, especially after interest. I'd deal with the weather and distance from family/friends to save 90k.
So, in summary, I'd drop box 2; take my subjectivity with a grain of salt of course.