I think maybe we spoke about this before? I took a summer session at Sophia in 2004. It was great and the classes were pretty good; all English and the teachers were American. The few Japanese students in these classes always had translators out and were typing away, trying to follow everything that was being said.
The combination of intensive language courses and living abroad could potentially mean you really ramp up your Japanese and learn a LOT. Take advantage of it!
As for the other stuff, you'll get used to getting around and all that stuff pretty quickly, I'm sure. Have fun!