rape park behind GDS can be rather pleasant on a sunny day, but by taking a 2 minute detour and walking down borough high st you avoid it completely, saving your life, your wallet and your innocence at night. But seriously its not that bad... only 2 students have been mugged this year walking through it, which is nothing compared to some of the other places!
living in flats totally doesnt stop you socialising. At uni everyone wants to make friends, so everyone finds a way to socialise. In fact i think its better because you get really close to your flat, and then as you make friends from your course or clubs in other flats you end up meeting all of their flat mates, so accquire 7 extra friends for every one friend.
Usually to get a non-standard room you specify on the application, as alot of people want them, because they're alot a cheaper. So i wouldnt worry about randomly being given one.