I lived in Birks Grange for my first year, so should be able to answer some of your questions.
I understand your concern about being isolated in a studio, but if you make the effort to socialise, you should find it absolutely fine! There are plenty of common areas, snooker and pool tables in the Central Block, and a bookable communal kitchen if you wanted to cook a bigger meal with friends. There is a real sense of community around Birks Grange - there are always people around to chat to, do your washing with, eat with, etc. if that's what you choose to do!
I really enjoyed my time in Birks - it's just a ten minute walk (uphill!) to the centre of campus, about 20 minutes from town. There are also plenty of buses running to and from town, ideal when the weather is miserable or you're on your way back from a night out!
I hope this has helped in some gave - feel free to get in touch with any other questions you have!
University of Exeter Student Ambassador