Travel tips for 6 days in Japan

Hi

We are arriving in the afternoon to Narita airport and plan to get a 7 day travel pass.

our plan would be to go to Nakone (via Odawara station) and Kyoto.

we fly out from Narita 17.00 hours on our last day.

1. do you think this trip is manageable in 6 days?
2. do you need to pre book ticks for the JR shikansen or can we just tuen up at the station?
3. can we get from Odawara to Kyoto?
4. is it realistic to travel from Kyoto to Narita in a day for a 14.00 check in?

we are travelling as a group of 5 - 2 adults and 3 children 13, 10 and 8 years old

many thanks

alison