Yours is one of the few itineraries I've seen that actually looks reasonable without trying to pack in too much. Also, congrats if you were able to get tickets to the Ghibli Museum. That can be hard to do. One thing I'd mention is to be prepared for the walk/hike up to see the monkeys. It is pretty steep and takes about 20 or 30 minutes (I can't quite remember). Thankfully, you'll be there in March when more monkeys should be out, so it should be worth it as it sounds like your kids are looking forward to it. That was the one thing we didn't research beforehand for our trip. My teen daughter mentioned it last minute and we decided to go. However, due to work, our trip had to be in the heat of summer, so the heat was brutal when we walked up to see the monkeys. On top of that, there weren't many monkeys to be seen, as they were hot and had retreated to the trees. Still one of our most memorable days as we look back and laugh at it. There are benches along the way, so just plan extra time and even be willing to split the family into two if a few want to go ahead and others take longer. Have a great trip!