Hello John

I will leave most of your questions for those with experience of Japan.

Here is a website for tours to Fuji from Tokyo:
http://www.jtb-sunrisetours.jp/

This is a very useful site for checking trains:
www.hyperdia.com. You can check for trains to "hakoneyumoto" which is a gateway to a viewing point for Fuji.

What hotel are you staying at in Tokyo? We can make better recommendations if we know what side of town you are in.

Jan 24- Only one day for Disney? You realize there are two parks right? Tokyo Disney and Disney Sea. Both are worth a day and you kids will probably agree. There are shuttle buses from certain Tokyo hotels. We have been to both venues twice and in January it will be cold especially at DS as it is right on the ocean. The cold ocean breezes begs you to dress properly.

http://www.japan-guide.com/e/e3016_land.html

http://www.japan-guide.com/e/e3016_sea.html

Jan 25-Ueno park is a good idea for the kids.

http://www.japan-guide.com/e/e3019.html

There is also Ameyokocho right outside one of the entrances across the street from JR Ueno station where you can have a bite for lunch and some interesting shopping. The kids will love all the toys and candies for sale here for sure.

http://www.japan-guide.com/e/e3012.html

If you have time after that hop on the subway for one stop down the line and check out the Sensoji Temple and the Nakamise Dori(shopping street) that leads up to the temple.

http://www.japan-guide.com/e/e3001.html

Jan 26 - Harajuku and Shibuya would be a good place to take the kids with Yoygi Park too. They would probably love to visit Kiddieland while they are in the area.

http://www.japan-guide.com/e/e3006.html

http://www.japan-guide.com/e/e3007.html

Jan 27 - You can see views of Fujisan from several points on the Hakone Loop if you wanted to do a day trip and see there if the weather cooperates. The loop or round course is explained in detail here:

http://www.japan-guide.com/e/e5210.html

http://www.japan-guide.com/e/e5200.html

I've been to Fujigoko but its better to stay overnight there. There is a huge amusement park a few kilometers away from Kawaguchiko(the main village of the five)that the kids would enjoy.

http://www.japan-guide.com/e/e6900.html

If you stay in Kawaguchiko maybe splurge for a ryokan stay. We stayed here and thoroughly enjoyed ourselves. Fab views and a quaint little town.

http://www.japaneseguesthouses.com/db/fuji/konanso.htm

a few ideas to mull around.....

Aloha!