[atheistwithfaith]

Just to add to the point about roommates and sakura house. Most rooms that sakura house rent out have the opportunity to be split between two people - however you will be sharing a kitchen / bathroom with potentially 4-5 other people. Most people at sakura house are just there temporarily (although I think the girl who was in the flat I was in was one of their longest residents - 4 years!).

Unless you have some other special skills that you have not mentioned, or are very successful poets/writers - then I do not see how you will be able to receive a work visa to stay in Japan as I cannot see a Japanese employer going through the rigour of applying for a visa for someone who won't be bring any skills they can't find in native Japanese (and English teachers with a degree are ten-a-penny).

From what I know, becoming a Japanese citizen is an extremely long and arduous process. You must have lived in Japan continuously for 5 years to be even considored (having lived their longer will aid your application) and in becoming a citizen you renounce your citizenship of the USA (which, as cavalier as you are about now, has many benefits).

One thing that would massively help your search for work in teaching english would be obtaining a TESOL / TEFL qualification from a respected body.