I don’t know where that statistic comes from but since ~30% of undergrads are (originally) from OOS, that can’t be correct (if by “commuter” you mean local in-state students).
There’s housing on campus for about 4000 students, plus another 1000 or so in off-campus apartments just down the hill (excluding another 1500 or so in grad apartments) and about 4500 freshmen. So I think a bit over 50% of freshmen live on campus (anyone who wants to can do so). After that honors students can get housing if they want it reasonably easily, most others usually rent houses or apartments, some close to campus, some further away. A few hundred students live in the Greek houses. External rentals are usually a bit cheaper than university ones.
D has three different social groups, her closest friends in her scholarship group (since they all live together), then also her sorority and her major. Her friend group takes a lot of weekend trips (particularly skiing and backpacking), and has stayed for the summer to do things together (climbing, rafting, hiking, etc). They often rent AirBnBs or stay in friends’ cabins if it’s too cold to camp. Their go-to social center this year has been the climbing gym (not least because it’s been open all year).