I checked the link below and the Parking page that can usually be found there has not been posted yet.
https://www.usna.edu/PlebeParentsWeekend/index.php
I did a quick search online and found plenty of specifics for certain events such as Commissioning Week, but not PPW in the past.
In general, you can park in a spot or lot not marked or reserved for staff, faculty, midshipmen 1/c or other specified use.
Parking overnight - though I could not find the specific reference, I would expect day visitors to the Yard are not allowed to leave cars overnight. There simply is not enough parking. If 1100+ families get passes and leave cars overnight (a little hyperbole here, but there is potential), it makes it very difficult for the staff and other employees who drive on each morning, including weekends, to find parking.
I expect most folks will park in the Hillman City Garage or other parking, walk in for events and just do drive-ons to collect or drop off their plebe. I don’t know whether the Stadium parking/shuttle arrangement will be activated.
I’m sure PPW-experienced posters will have some advice to offer.