Hi @libsea…the OP has been quiet for a while, so I am jumping in with the bits that I am familiar with
re: going home / breaks
So, this is one of the biggest differences between Oxbridge & other unis: it turns out that the words “vacation” and “holiday” are not synonyms. “Vacation” at Oxford means you “vacate” your room - as in, move out entirely*- and go home to study what you have been working on during term. End of term exams (called “collections”) are sat when you come back from “vacation”. The idea is that you use those breaks to study the parts of the syllabus that you didn’t get to during term.
There are internships in some fields (law, finance, consulting are the usual suspects), and some ongoing research projects (mostly STEM), but it’s really secondary- except summer after second year, when the big firms recruit. The terms are super-intense so the first part of the vac is usually recovery, and the last part is studying for collections.
Going home for Thanksgiving is really not an option, not just for distance, but also because of where you are in the term- you finish up the 1st week of December. There is an annual joint Oxford-Cambridge ski trip (called Varsity Trip- there’s a video if you do a search) the week after Michaelmas term ends, when some 3K+ Oxbridge students hit the slopes together. Collegekid preferred a smaller getaway, so a small gang of pals would go various European places together before heading home for break.
re: recruitment in the US
It matters what you want to be recruited for! but Oxford carries plenty of weight as a name. One thing to be aware of is that US colleges get out earlier than Oxford does, so a lot of US internship dates will start before you are ready. Oxford also goes back a lot later, though, which can be an advantage in negotiating a later start date!
re: Americans at Oxford
There are three main categories of American students at Oxford, and they don’t interact much: grad students, visiting/study abroad** and full time undergrad. There are so few full time American undergrads (~200 across 45 colleges & PPHs, out of 1700 total US students, out of 12K undergrad/24K total students) that you will probably be aware of most of them. But- they really don’t stick to each other- nor, with the exception of some of the Chinese and to a lesser extent Indonesian students- do other international students stick with their compatriots. You may be the only American in your college; unless you are at Catz (St Catherine’s) or Teddy Hall (St Edmunds), which host a lot of visiting / study abroad students, you are unlikely to have more than a couple of others. From your other thread you are a potential Historian, so there are likely to be a few fellow Americans in the various combinations (+ Pol / Eng / Econ / Modern Lang). At Oxford you are known more by your subject and college than anything else.
Finally, some unasked for advice: Oxford is great if you really, truly love your subject. The HisPol Collegekid would give me books for Christmas that were written by her tutors and lecturers- it is really amazing. But if you just kind-of like history compared to your other subjects, think carefully. It is super intense, and it’s all you do for 3 years.
On the other hand, if that sounds great to you- get cracking on making sure that you can take the HAT, on finding a paper that you can use to submit with your app and (esp) making sure you have your APs lined up!
*UK students take all their stuff home for vacations; most colleges have a place for international students to store their stuff and a few colleges will let you pay extra to keep your room through the vacations. You can infer from this that ‘doing up the dorm room’ is not a thing in the UK!