I'd say proceed at your own risk. It's there to be had, but I think when you go somewhere else in the world, you will see that we have it pretty good here. Just expect to be parted from a lot of cash if you don't know what you're getting into. Furthermore, understand that there is a "working relationship" between the police and Yakuza so don't expect much sympathy if something goes wrong. Everything you have heard about Japanese kindness, politeness, and hospitality is true and then some. However, it should be noted that they are very sticky about rules and protocol. Stay within them and you'll be treated like gold. Step outside of them, don't get caught and if you do, they're not very understanding.
As far as getting random girls to your hotel, here's the thing. If they're not married, there is a good chance that they still live at home and have a curfew regardless of their age. I met a girl in Shinjuku, we got together a couple days later. We went sightseeing then went out for dinner. Then back to my hotel. It didn't take much to get her back there, nor did it take much for things to start happening between us. At around 11, she says that she has to go home as her parents were expecting her back. I walked her to the train station then went out drinking. BTW, she was 24, university-educated, had a good job and was still at home as she is "traditional". I am in my early 40s, and did not lie about my age. The age gap isn't such a big deal there.
