We did not visit the castle itself, since we were passing through there, next time we will take a bigger walk and extend the article. The area is open and the place is very beautiful at sunset, you can sit on the grass, on the banks of the water channel.
Getting there: parking N 47 36.932 E 1 30.666. There is a direct shuttle bus from Paris (info). By train from Paris Austerlitz station to Blois-Chambord station, then by shuttle to the castle (April - November), the shuttle schedule can be downloaded here.