There is absolutely /no/ problem visiting a location prior to the interview. /ubbthreads/images/icons/smile.gif All you have to do is call the 1-800 number, get the direct number to the local office you plan to visit, give them a call to coordinate and make sure someone is there to welcome you, then go visit.
Shouldn't be any problem at all, as long as you can make it there when the instructors aren't busy.
As to your second question, not sure I understand fully what you mean, but I'll try to describe it;
Some people go through the program 'alone', some do it paired up with various other students, some do it (As I did it) paired up with the same guy all through the program. It depends on if someone's signed up to start at the same date that you are, and the schedule of the instructors at the location.
Any of these combinations have their advantages and disadvantages, so I wouldn't sweat it, no matter which one you get.
As far as training scheduling, it looks more or less the same no matter which one of these you do. You might backseat once in a while, if you want to, but otherwise it's mostly just you and the instructor, no matter if you have a training partner or not.
The time in the training where a partner comes into play is during your cross country flying.
If you have any other questions, or any of my answers needs clarification, don't hesitate to follow up. /ubbthreads/images/icons/smile.gif