I went to Oxford for the first time this weekend. I feel I should dispel some common misconceptions;
1) A wand-wielding Daniel Radcliffe will not jump out at you even though you continually expect it
2) Oxford college is not one campus but instead is made up of colleges and accommodation that are dotted throughout the centre
3) Despite the sunny photographs of the colleges, it does rain there. You may be forced to wear a poncho. It will prove embarrassing.
The colleges I liked best included Balliol (lovely gardens), Magdalen College, New College and Christ Church (where HP scenes were shot!). Definitely try get to Blenheim Palace (Churchill’s birthplace) as well if you can and embrace punting (but only the chauffeured variety!) The botanical gardens are also worth a look (they are holding a pumpkin-weight guessing competition there and who doesn’t love a competition that involves no skill?!)