Golden Week Seat Reservations

Hi there,

I'm going to be travelling during Golden Week and am concerned about getting seat reservations during this busy period. As I know you cannot make reservations until you arrive and activate the rail pass, so I would like to check:

I arrive on 29th April and need to travel Tokyo - Nagoya, Nagoya - Takayama on 3rd May. Therefore, will I have problems making a reservation only 4 days in advance when I arrive in Tokyo? Is there anything I can do about this?

I also need to travel from Toyama to Kyoto on 6th May.

thanks!