[jasonbvr]

Hi Becky, I don't think I can answer your questions as well as Nyororin so we'll hope that she spots your posting. But here is my take on some of them.
As far as a part time job goes, it really depends on where you are from. I don't the specifics of trying to work with a student's visa, but I assume that you would be working "under the table." This means pseudo illegally, but you would definitely be able to find some English students by posting on some site like mysensei.com and a few others. These let you find your own students, charge them what you like and take straight cash payments. There are other opportunities too. I saw an advertisement the other week for female staff at an English conversation coffee cafe, but I don't know what sort of visa you will need.
As far as dating, I am interested to know what your ethnic background is. Regardless of what it is, you will find it quite easy to find a nice guy to date. I only mention this because, well I don't know if it is so much a thing now, but Korean men and women were sort of idolized in the past because of huge hit Korean movies and TV shows. Either way though, there are plenty of singles out there.
Studying should be fairly easy. Nippon schools are fairly laid back by the time you get to college. You would probably be studying primarily Japanese so difficulty would depend a lot on your level and commitment.
Hanging out I guess depends on what you what to do. There are plenty of clubs and bars around colleges I am sure. Drinking age is twenty, but for a gaijin they don't ever check. I am not even sure they check Japanese for ID. Plenty of sports enthusiasts to get involved with. Excellent skiing/snowboarding here with a nice long season. Skating, music, lots of art shows in Tokyo, etcetera, just depends on what you are interested in.

Anywho, ganbatte kudasai, ja ne...