Office Hours in December for check in?

Check-in time is 3PM all year. In the winter, when staff is not readily available, use the yellow phone at the campground office porch to check-in, or to rent a campsite (credit card, cash, or check). There is also a self-pay kiosk (cash or check) at the same location if the yellow phone service is not available

By 5:00 PM at latest.

Before 5

I think before 5