Hi there! Here are some tips and tricks I wanted to share with you if you wish to visit Oxford or if you are a future intern in that city. I hope this could be useful.
Accommodation
Try to find a room, a place, close to the City Center or around. The best places for me are St Clement's, Iffley Road and Cowley Road. Not too far away from the City stand Rose Hill, Iffley, Cowley, Headington Hill, Osney and Jericho.
I've found mine through Airbnb. They have really great deals for long term staying. It is also worth asking the Colleges or the place you will have your internship because they can offer rooms, at least before the term start.
It exists several websites dedicated to students accommodation (Spareroom, Rightmove,...). These could be great but you probably should visit the place before coming (my opinion).
Where to go? What to do?
You will never get bored in Oxford. There are so many things to do, to visit, for all different kind of interests. If you are a shopaholic, The Westgate Center will welcome you warmly. Once you arrive in Highstreet, plenty of little and big shops and of course the famous Covered Market will greet you.
If you could visit the Sheldonian Theatre that would be nice too! The Ashmolean Museum has free entrance to its permanent exhibition and a nice roof terrace. Not that far, you can find the Weston Library.
Colleges are one of the most amazing buildings in Oxford. You should visit them. Christ Church is well-known, as well as All Souls and Magdalen College. Of course, you have to come across the Bodleian library, its Radcliffe Camera and the University of Oxford Botanic Garden.
Walking along the Thames' river is a thing you can't escape! Finally, Oxford is well located if you plan to go to London, Bath, Reading...
The Bridge of Sighs
Pubs and restaurants
I would definitely say that Cowley road is a great place for that, especially when you are getting hungry. I love the Everest Nepalese Restaurant and the Cafe Coco. There's a lot of exotic food but in the Red lion's pub, they made a good traditional Sunday Roast Chicken.
If you fancy a drink in a nice typical english pub, please do not hesitate to go to the Turf Tavern, the Magdalen Arms, the Mad Hatter or the Cape of Good Hope. For a nice view of Oxford, Varsity Club and its rooftop will amaze you.
Saving money?
Eventbrite is a nice website and application showing the next events in Oxford and its surroundings (parties, lectures, outside and inside activities,...) and some are free!!!
The supermarkets are places to know. To cook at home can be reasonable. Tesco, Sainsbury's, Cooperative and Lidl are the most abundant.
Transportation
No matter from which London airports you will land, you can find a bus to go to Oxford at any time. After that, the Oxford Railway Station could be useful to visit London,... it is a good thing to buy a ticket online because you may find some nice discount.
In Oxford, if you are brave enough and not scared of the "driving on the left-hand size", riding a bike is for you! It is the most common transportation using here. You can find cheap bikes on Gumtree. Otherwise, buses are coming very often. One single ticket is a bit expensive but there's a day ticket, or buses' pass for a week, month,...
Facilities
This depends on your future work place but you will be considered as a student. Ask your colleagues, you may have some privileges such as discount in shops, at the University Gym and to Museums,...
Christmas period
Christmas magic is here in Oxford, you will not miss Mulled Wine and Mince Pies! The Blenheim Palace is worth to see. At the beginning of December, Broad street becomes a cute Christmas Market. If you plan to go to London, Southbank Centre Winter Market and Hyde Park Winter Wonderland will make you happy.
That's it! Here was a summary of what I could tell you about my own experience.