Day 1 - "Castle and Park"
Don't sleep on Nagoya. Some people tell me this is actually their favorite Japanese city. It's bigger than you think. Sometimes seedier than you'd expect. An abundance of restaurants.
This day you'll do the castle and surrounding park, which are both excellent. Also, the park surrounding the Mirai Tower is fantastic. Great restaurants, coffee shops, dessert places, and various shopping. The locals would hang out there at night in droves.
Note - Grand Base is a good family hotel chain. There are two in the city. Recommended.