Castle is closed
Good
Seems like a good place to start a tour around the castle.
Because of the earthquakes in April 2016, it will take a while before its possible to get directly to the castle, though.
Cheaper than I thought for such a large tourist attraction downtown
Parking is very reasonable. Rate is 2 hours for ¥100 and every hour after is ¥50 till 6:30pm. This only applies to kei-cars. Regular cars cost slightly modified more.
It is pretty full on Saturdays and Sundays! Very near Kumamoto Castle.