@Big Shrek I appreciate the advice, I'm actually USAF, and am half Japanese/Thai. I was in Tokyo back in '07 and had a blast then. I know a little bit of Japanese, enough to barely get around (Ask where X is, how much is Y in yen, my name is etc.)
No worries about getting involved with the local girls, seeing as I have one that already like here in the states. Also, yes, Yakuza, not wise to get too chummy with them, that and Pachinko parlors are a definite no no.
Reading around, it looks like it's pretty much impossible to have any kind of firearm in Japan nowadays, even more so if you live off base. Handguns are out of the question, so I'm not going to even try with that.
I may look into one of those plastic laser trainer guns, I don't think they'll have any problems with those, seeing as it's VERY obvious that it's not a real, functioning firearm.