hahah Yes it does sound that you might not be proficient in skiing.
I recommend a point and shoot. to fall on your DSLR is not funny. I usually keep my PNS in my jacket, so whenever I am skiing I just take it out and snap. Much easier. Canon seems to have a cute all weather on...
Well if you like cosplayers then it's ok... :-)
I prefer Furano and Niseko... I would recommend the prince hotel. Ski in and ski out resort with decent enough food. Mountain is good for skiers and snowboarders alike.
You ski at noboribetsu in San-laiba ?
It's seems pretty packed... and looks like you plan to do alot of walking...
If you are going to Ueno.. might as well head to Asakusa (http://en.wikipedia.org/wiki/Asakusa)...
It's generally safe... just stick to the touristy places if you are worried.
Of course avoid certain places... Like red light district.. which is where most of them are.
Where were your friends drinking anyway... in tokyo ?