The best time to visit Great Smoky Mountains National Park is when it's less busy which is in June, July and August or in the Fall.
You cannot metal detect in the Great Smoky Mountains National Park as metal detectors and mineral detectors are not allowed in the Great Smoky Mountains National Park.
Alcohol is allowed in the Great Smoky Mountains National Park.
The Great Smoky Mountains National Park allows alcohol to be brought into the park and consumed in the park as long as you are legal of age to drink it which is 21 years or older.
However if you do get drunk and disorderly you could get arrested and possibly banned from the Great Smoky Mountains National Park.
That happened to a guy who was camping there a few years ago and I was not far from him.
He got arrested because he was too drunk and causing issues and he got banned from the park.
So just enjoy the alcohol in moderation and avoid getting drunk and you will be okay.