How much time should I allot to visiting the mansion and grounds?

I spent two hours there.

I suggest 2 hours because the views from the grounds are so extraordinary

At least an hour. So much to see.

Minimum is half an hour for outside. Take a picnic- there are tables at the overlook!

I'd say up to an hour.

30 min to an hour depending on how much you explore

If U would take a walk or take a picture just 30mins.

1.5 to 2.5 hours