Where should I stay beside shinjuku area ?

Yes, it will be the middle of winter, so most people need to wear a winter coat outdoors. You will see snow on Mt. Fuji if the weather is clear.

Do you mean that you are taking a day trip from Lake Kawaguchi to Hakone, I.e back to Kawaguchi-ko the same day?

Looking at your list, I'd recommend one of the Prince hotels in Shinagawa as they are stops for the Express buses to Haneda. Another place that you might want to look into is the Sunshine 60 in Ikebukuro. There's easy access to shopping, nightlife, eateries, etc. and 60 also has a bus that is targeted for Haneda. The last place I'd suggest would be Odaiba. Very close to Haneda and full of entertainment options.

Hi Koko,

I be travelling to lake kawaguchiko for a nite stay from osaka , then go to hakone next day.
Is not possible for me to travel hakone & lake kawaguchiko for a single day right?

But I wonder my luggages should I hand carry to travel or get courier delivery back to my next hotel?