Yeah I've watched some of your videos too.
A year in Japan sounds great, I never been there more than a half year!
You might surpass me in Japanese if you practice by talking with people a lot. You already have a pretty solid basic knowledge. I had a friend that studied in Japan for a year in one of those language schools, but all he did was buy manga and video games and sat in his room to play every day. He pretty much only spoke Japanese in class and when going to the convenience store. I probably met more new people in my last three week trip to Japan than he did in a year, and I can be a bit shy sometimes depending on my mood.
You will probably have time to play games too, so don't do it like him. Japanese people are often very excited to befriend foreigners so it's quite easy to make friends once you get to talk with some (memorizing how to introduce yourself is very useful).
Be sure to memorize how to ask for the road and to understand directions (phrases like "○○をさがしているんですが" are indispensable). There's probably a chapter about asking directions in most Japanese text books. If you can do that you will have no problem in finding your way.
May I ask what you are going to do for a year? Study? And where are you staying?