Osaka - Kyoto (half day tour) - Tokyo

Hi..I need advice
I plan to have winter trip to Japan
I will go with family, 3 persons, inc. 4 years old kid
I plan 3days in Osaka, on day 4th I will go to Kyoto than Tokyo.
My question is if I go to Kyoto in the morning and get half day tour in Kyoto after that go to Tokyo by train in the same day, is it possible for family traveller like me? If yes which station and by what train and how much the fare when we go from kyoto-tokyo? Where can we keep our luggage when we take half day Kyoto tour?
Additional question, where is the cheap place for skiing and snowboarding near Tokyo? I rated many suggest to gala yuzawa?
Thanks anyway

A half day in Kyoto isn't much time to see anything.

Adult fare Kyoto to Tokyo is around 13,500 yen for a reserved seat on Shinkansen. The 4yo child can sit on lap and travel free is not occupying a seat. Exact pricing can be found on www.hyperdia.com

I'd consider doing Kyoto another full day. Then Osaka on the day you travel. Leave your bags at the hotel. Travel around and sightsee. Then mid afternoon return to collect bag and go catch the train.

Do 1 day in Osaka, then do 2 days at Kyoto, then the half day in Osaka (or steal an extra half day in Kyoto) before heading back to Tokyo. Kyoto has way more to offer. Leave your luggage in a coin locker at the station then you don't have to return to your hotel.

Gala Yuzawa is nice and close to Tokyo. It also has good facilities. There are other places too (e.g. Karuizawa) but surely Gala Yuzawa would suit your needs?