Keep doors closed to rooms you don't want disturbed. The garage is another area for concern. More dangerous chemicals may be stored here, including garden pesticides and antifreeze, both regular and windshield-washer kinds. Store them safely and thoroughly clean any spills. Then there is the yard.
Puppies are inveterate diggers.
If you don't want the flower beds turned upside down, fence them off. Maybe a lock would be in order, or at the very least a sign reminding people to shut them. Use common sense. And when you are with him, keep an eye on him. He can get into trouble in an instant.