It sounds to me like Williams may be a home for you. I’m going to preface this by saying that I’m super biased, being a current student and tour guide, but based on what you said it seems like Williams fits well. Let’s go through your criteria step by step, shall we?
The campus: We have buildings. Pretty buildings. Beautiful buildings, actually, and there’s a pretty cool dichotomy between old and new (see: the new library, which is magnificent and built from the shell of the original Stetson library). The buildings are all furnished with modern appliances, of course, but some - like West building - have been around since the college opened in 1791.
Not Cliquey: the entry system takes care of that. You’re living with people from all walks of life from day one, people who you may never have met otherwise: athletes, musicians, actors, etc. all thrust together into one entry. And the great part is, you’re all friends. No, really, you are. Most people make their first friends in the entry and then branch out into their respective social circles, but Williams makes sure that the cliquey friend groups who are only interested in themselves never form. I’d argue that, out of every school you’re probably interested in, Williams does the best job in this category.
No Frats: We have no frats. Check.
Rural Area: Williams is rural, and this isn’t a bad thing or a good thing, it’s a GREAT thing. You have your whole life to live in a city, but you’ve only got four years to live in the woods. Williams people tend to be pretty outdoorsy - although this is obviously not a hard and fast rule - and you’re encouraged to take advantage of the nature all around you through random days off like Mountain Day and Winter Carnival. It’s seriously amazing. Plus, we have stores and restaurants and stuff, so you won’t be culturally starved. Visit, and see if you feel overwhelmed by the nature, or if you feel inspired by it. It’s a feel thing, but I highly recommend it. (The unnamed A-school is lacking in this department, by the way)
Partying: At Williams, there are parties. People also consume alcohol. This is because it’s college, and people enjoy such activities. However, there’s literally zero pressure to do anything, and the parties tend to be less raves and more hang out with friends while getting steadily drunker (or not). There are a few classic college parties, but they’re off-campus and easily avoidable. I never go. I actually really enjoy the majority parties here and I seldom drink at them. In fact, I first drank almost halfway through the year - as a personal choice, not being pressured into it - and had spent the first half having just as much fun as the rest of them. If you still feel like parties aren’t your thing, however, Williams sets up a ridiculous amount of non-drinking activities, as do its students. There’s a late-night baking club called Get Baked, tons of performances every weekend, games to go to, etc. Not drinking at Williams is stress-free and totally easy.
Academic Rigor: Williams is hard. It’s really hard, actually. I find myself challenged in every class. However, it’s not impossible, and Williams doesn’t want it to be impossible. The library closes every night at around 2:30 because Williams just doesn’t want kids staying in there all night, wasting their lives and their sleep. I’ve never had to pull an all-nighter, and I don’t really plan on it. Plus, the work isn’t busywork like in high school. I really feel like everything I’m doing is worthwhile and helping me progress in my learning. So it’s hard, yes, but I prefer it to any alternative.
If you have other questions, ask. I have answers.