At most schools you choose your own classes after your first year. There are rarely classes on Friday afternoon – even in the first year nobody likes them and after that, no one would sign up for them. The biggest issue can be yom tov, but those usually are at the beginning of the semester. Schools usually make allowances for frum people, though the degree to which they make the allowances differs. some schools will video the classes on request. Others will only tape it. Some schools make a big fuss about not recording class for travel days – i.e. erev yom tov. I actually know someone who was refused a recording when he had to miss class for a funeral, because he wanted to leave in the afternoon and the funeral wasn’t until the next morning.
My understanding is that there is not a large frum community near Stanford. Frum people at Yale associate with the Waterbury community (in addition to whatever frum life is around Yale’s campus). Frum people at Columbia/NYU can live in Brooklyn. Frum people at Harvard tend to go off the derech.