Not sure if anybody answered this one - as the thread is moving very quickly, but as another orthodox mum - with a DS at university and a DD looking at Open Days at the moment, I am possibly better placed to answer than the OP, given that here children are probably still quite young.
First of all, mostly the Charedi community (both Chassidic and not) mostly don't go to university - they go on to study in yeshiva or seminary and/or gets jobs that don't require a degree - working in a/owning a shop, business etc. Sometimes they will, after their yeshiva time, do short term courses such as diplomas etc. There are exceptions, and even where they do, they will generally try and go to universities near where they live - eg London universities, so they can live at home.
The modern Orthodox community (which we are in) do mostly go to university, but even there, a lot try for London or Manchester universities so that they don't have to leave home. My DS is an exception, and even with him, one of his key criteria was to go somewhere where there were numbers of Jews, so at least there is a decent JSOC. That limited the universities that he was willing to consider - and he is finding it very tough, even so, being one of the only boys on campus with a kippah, and I believe has been taking it off a lot. It is not fun.
My DD is now looking at universities and we are having a bit of a nightmare about the intersection between somewhere where there are Jews, and somewhere that do what she wants to do. She is very worried about being one of the few religious Jews at Bristol, for example (Bristol of course having an awful reputation for antisemitism) - but they are really doing the perfect course for her. Other options are going somewhere where she will have virtually no Jews at all (the JSOC apparently had six members this year, and that is the first year they have operated, and that is across campuses) but coming home every Friday so she can be home for Shabbat.
Note by the way that because of Shabbat, we are very restricted in the Open Days we are going to. In order to make the only non Shabbat Open Day at Bristol work, we are going up on the Thursday night, and staying until Sunday, because we can't see how we can see what we want to see on the Friday and get home in time for Shabbat. Not fun, and a lot of people we know wouldn't go to those kinds of lengths, they would just give up on the idea. We are relatively unusual in that my DC are willing to look at this at all. I think it is a nice opportunity for us to see exactly what kind of community there really is in Bristol to provide some level of support for DD.